Python第二天
上节小结：
1、解释器出现乱码问题：我们在totepad++上编写代码，然后放到windows的终端去执行的时候，如果有汉字会被解释成乱码。
2、这里我们用一个中间代码(这两种编码的母码)进行转换
例子：
#!-*- coding:utf-8 -*-
temp = "李杰"
#解码，需要指原来的编码的类型
temp_unicode = temp.decode("utf-8")
#编码，需要指明将要编码的类型
temp_gbk = temp_unicode.encode("gbk")
print(temp_gbk)
一、运算符
1、算数运算：就是数的加、减、乘、除以及乘方开方等数学运算
2、比较运算：两个或多个同一类的事物进行比较，当用运算符比较两个值时结果是一个逻辑值而不是True或者False的运算符号。
3、赋值运算：优先级低于其他运算符，所以对该运算往往最后读取。
4、逻辑运算：逻辑运算又称布尔运算布尔用数学方法研究逻辑问题，成功地建立了逻辑演算。逻辑运算通常用来测试真假值，最常见的逻辑运算就是循环的处理，用来判断是否该离开循环或者继续执行循环内的指令。
例子： and运算，都为真时为真 >>> 9 > 8 and 9 < 10 True >>> 9 > 8 and 9 > 10 False or运算，有一个为真的时候即可为真 >>> 9 > 8 or 9 > 10 True >>> 9 < 8 or 9 > 10 False >>> not运算，假为真真为假 >>> not 6.2 <= 6 True >>> not 6.2 >= 6 False >>>
5、成员运算：
一、基本的数据类型
有关类的概念：说到类就不得不提对象，对象是对客观事物的抽象，类是对对象的抽象。它们的关系是，对象是类的实例，类是对象的模板。
1、整型(int)
Python可以处理任意大小的整数，当然包括负整数，在程序中的表示方法和在数学上的表示方法一致。例如：1,1564，-872,0等。
在32位机器上，整数的位数为32位，取值范围为-2**31～2**31-1，即-2147483648～2147483647
在64位系统上，整数的位数为64位，取值范围为-2**63～2**63-1，即-9223372036854775808～9223372036854775807
class int(object): """ int(x=0) -> int or long int(x, base=10) -> int or long Convert a number or string to an integer, or return 0 if no arguments are given. If x is floating point, the conversion truncates towards zero. If x is outside the integer range, the function returns a long instead. If x is not a number or if base is given, then x must be a string or Unicode object representing an integer literal in the given base. The literal can be preceded by '+' or '-' and be surrounded by whitespace. The base defaults to 10. Valid bases are 0 and 2-36. Base 0 means to interpret the base from the string as an integer literal. >>> int('0b100', base=0) """ def bit_length(self): """ 返回表示该数字的时占用的最少位数 """ """ int.bit_length() -> int Number of bits necessary to represent self in binary. >>> bin(37) '0b100101' >>> (37).bit_length() """ return 0 def conjugate(self, *args, **kwargs): # real signature unknown """ 返回该复数的共轭复数 """ """ Returns self, the complex conjugate of any int. """ pass def __abs__(self): """ 返回绝对值 """ """ x.__abs__() <==> abs(x) """ pass def __add__(self, y): """ x.__add__(y) <==> x+y """ pass def __and__(self, y): """ x.__and__(y) <==> x&y """ pass def __cmp__(self, y): """ 比较两个数大小 """ """ x.__cmp__(y) <==> cmp(x,y) """ pass def __coerce__(self, y): """ 强制生成一个元组 """ """ x.__coerce__(y) <==> coerce(x, y) """ pass def __divmod__(self, y): """ 相除，得到商和余数组成的元组 """ """ x.__divmod__(y) <==> divmod(x, y) """ pass def __div__(self, y): """ x.__div__(y) <==> x/y """ pass def __float__(self): """ 转换为浮点类型 """ """ x.__float__() <==> float(x) """ pass def __floordiv__(self, y): """ x.__floordiv__(y) <==> x//y """ pass def __format__(self, *args, **kwargs): # real signature unknown pass def __getattribute__(self, name): """ x.__getattribute__('name') <==> x.name """ pass def __getnewargs__(self, *args, **kwargs): # real signature unknown """ 内部调用 __new__方法或创建对象时传入参数使用 """ pass def __hash__(self): """如果对象object为哈希表类型，返回对象object的哈希值。哈希值为整数。在字典查找中，哈希值用于快速比较字典的键。两个数值如果相等，则哈希值也相等。""" """ x.__hash__() <==> hash(x) """ pass def __hex__(self): """ 返回当前数的 十六进制 表示 """ """ x.__hex__() <==> hex(x) """ pass def __index__(self): """ 用于切片，数字无意义 """ """ x[y:z] <==> x[y.__index__():z.__index__()] """ pass def __init__(self, x, base=10): # known special case of int.__init__ """ 构造方法，执行 x = 123 或 x = int(10) 时，自动调用，暂时忽略 """ """ int(x=0) -> int or long int(x, base=10) -> int or long Convert a number or string to an integer, or return 0 if no arguments are given. If x is floating point, the conversion truncates towards zero. If x is outside the integer range, the function returns a long instead. If x is not a number or if base is given, then x must be a string or Unicode object representing an integer literal in the given base. The literal can be preceded by '+' or '-' and be surrounded by whitespace. The base defaults to 10. Valid bases are 0 and 2-36. Base 0 means to interpret the base from the string as an integer literal. >>> int('0b100', base=0) # (copied from class doc) """ pass def __int__(self): """ 转换为整数 """ """ x.__int__() <==> int(x) """ pass def __invert__(self): """ x.__invert__() <==> ~x """ pass def __long__(self): """ 转换为长整数 """ """ x.__long__() <==> long(x) """ pass def __lshift__(self, y): """ x.__lshift__(y) <==> x<<y """ pass def __mod__(self, y): """ x.__mod__(y) <==> x%y """ pass def __mul__(self, y): """ x.__mul__(y) <==> x*y """ pass def __neg__(self): """ x.__neg__() <==> -x """ pass @staticmethod # known case of __new__ def __new__(S, *more): """ T.__new__(S, ...) -> a new object with type S, a subtype of T """ pass def __nonzero__(self): """ x.__nonzero__() <==> x != 0 """ pass def __oct__(self): """ 返回改值的 八进制 表示 """ """ x.__oct__() <==> oct(x) """ pass def __or__(self, y): """ x.__or__(y) <==> x|y """ pass def __pos__(self): """ x.__pos__() <==> +x """ pass def __pow__(self, y, z=None): """ 幂，次方 """ """ x.__pow__(y[, z]) <==> pow(x, y[, z]) """ pass def __radd__(self, y): """ x.__radd__(y) <==> y+x """ pass def __rand__(self, y): """ x.__rand__(y) <==> y&x """ pass def __rdivmod__(self, y): """ x.__rdivmod__(y) <==> divmod(y, x) """ pass def __rdiv__(self, y): """ x.__rdiv__(y) <==> y/x """ pass def __repr__(self): """转化为解释器可读取的形式 """ """ x.__repr__() <==> repr(x) """ pass def __str__(self): """转换为人阅读的形式，如果没有适于人阅读的解释形式的话，则返回解释器课阅读的形式""" """ x.__str__() <==> str(x) """ pass def __rfloordiv__(self, y): """ x.__rfloordiv__(y) <==> y//x """ pass def __rlshift__(self, y): """ x.__rlshift__(y) <==> y<<x """ pass def __rmod__(self, y): """ x.__rmod__(y) <==> y%x """ pass def __rmul__(self, y): """ x.__rmul__(y) <==> y*x """ pass def __ror__(self, y): """ x.__ror__(y) <==> y|x """ pass def __rpow__(self, x, z=None): """ y.__rpow__(x[, z]) <==> pow(x, y[, z]) """ pass def __rrshift__(self, y): """ x.__rrshift__(y) <==> y>>x """ pass def __rshift__(self, y): """ x.__rshift__(y) <==> x>>y """ pass def __rsub__(self, y): """ x.__rsub__(y) <==> y-x """ pass def __rtruediv__(self, y): """ x.__rtruediv__(y) <==> y/x """ pass def __rxor__(self, y): """ x.__rxor__(y) <==> y^x """ pass def __sub__(self, y): """ x.__sub__(y) <==> x-y """ pass def __truediv__(self, y): """ x.__truediv__(y) <==> x/y """ pass def __trunc__(self, *args, **kwargs): """ 返回数值被截取为整形的值，在整形中无意义 """ pass def __xor__(self, y): """ x.__xor__(y) <==> x^y """ pass denominator = property(lambda self: object(), lambda self, v: None, lambda self: None) # default """ 分母 = 1 """ """the denominator of a rational number in lowest terms""" imag = property(lambda self: object(), lambda self, v: None, lambda self: None) # default """ 虚数，无意义 """ """the imaginary part of a complex number""" numerator = property(lambda self: object(), lambda self, v: None, lambda self: None) # default """ 分子 = 数字大小 """ """the numerator of a rational number in lowest terms""" real = property(lambda self: object(), lambda self, v: None, lambda self: None) # default """ 实属，无意义 """ """the real part of a complex number""" int
int用法示例：
1.def bit_length(self):==>返回该数字占用的最少位数
int.bit_length() --> int
num = 6 ret = num.bit_length() print(ret)
2、布尔值
布尔值和布尔代数的表达完全一致，一个布尔值只有True、False两种值，在Python中直接用True、False表示布尔值（请注意大小写），也可以通过布尔值计算出来：
>>> True True >>> False False >>> 3 > 2 True >>> 3 > 5 False
3、字符串（str）
字符串是以'',"",括起来的任意文本，比如"hello world"
字符串常用的功能：
*移除空白
*分割
*长度
*索引
*切片
class str(basestring): """ str(object='') -> string Return a nice string representation of the object. If the argument is a string, the return value is the same object. """ def capitalize(self): """ 首字母变大写 """ """ S.capitalize() -> string Return a copy of the string S with only its first character capitalized. """ return "" def center(self, width, fillchar=None): """ 内容居中，width：总长度；fillchar：空白处填充内容，默认无 """ """ S.center(width[, fillchar]) -> string Return S centered in a string of length width. Padding is done using the specified fill character (default is a space) """ return "" def count(self, sub, start=None, end=None): """ 子序列个数 """ """ S.count(sub[, start[, end]]) -> int Return the number of non-overlapping occurrences of substring sub in string S[start:end]. Optional arguments start and end are interpreted as in slice notation. """ return 0 def decode(self, encoding=None, errors=None): """ 解码 """ """ S.decode([encoding[,errors]]) -> object Decodes S using the codec registered for encoding. encoding defaults to the default encoding. errors may be given to set a different error handling scheme. Default is 'strict' meaning that encoding errors raise a UnicodeDecodeError. Other possible values are 'ignore' and 'replace' as well as any other name registered with codecs.register_error that is able to handle UnicodeDecodeErrors. """ return object() def encode(self, encoding=None, errors=None): """ 编码，针对unicode """ """ S.encode([encoding[,errors]]) -> object Encodes S using the codec registered for encoding. encoding defaults to the default encoding. errors may be given to set a different error handling scheme. Default is 'strict' meaning that encoding errors raise a UnicodeEncodeError. Other possible values are 'ignore', 'replace' and 'xmlcharrefreplace' as well as any other name registered with codecs.register_error that is able to handle UnicodeEncodeErrors. """ return object() def endswith(self, suffix, start=None, end=None): """ 是否以 xxx 结束 """ """ S.endswith(suffix[, start[, end]]) -> bool Return True if S ends with the specified suffix, False otherwise. With optional start, test S beginning at that position. With optional end, stop comparing S at that position. suffix can also be a tuple of strings to try. """ return False def expandtabs(self, tabsize=None): """ 将tab转换成空格，默认一个tab转换成8个空格 """ """ S.expandtabs([tabsize]) -> string Return a copy of S where all tab characters are expanded using spaces. If tabsize is not given, a tab size of 8 characters is assumed. """ return "" def find(self, sub, start=None, end=None): """ 寻找子序列位置，如果没找到，返回 -1 """ """ S.find(sub [,start [,end]]) -> int Return the lowest index in S where substring sub is found, such that sub is contained within S[start:end]. Optional arguments start and end are interpreted as in slice notation. Return -1 on failure. """ return 0 def format(*args, **kwargs): # known special case of str.format """ 字符串格式化，动态参数，将函数式编程时细说 """ """ S.format(*args, **kwargs) -> string Return a formatted version of S, using substitutions from args and kwargs. The substitutions are identified by braces ('{' and '}'). """ pass def index(self, sub, start=None, end=None): """ 子序列位置，如果没找到，报错 """ S.index(sub [,start [,end]]) -> int Like S.find() but raise ValueError when the substring is not found. """ return 0 def isalnum(self): """ 是否是字母和数字 """ """ S.isalnum() -> bool Return True if all characters in S are alphanumeric and there is at least one character in S, False otherwise. """ return False def isalpha(self): """ 是否是字母 """ """ S.isalpha() -> bool Return True if all characters in S are alphabetic and there is at least one character in S, False otherwise. """ return False def isdigit(self): """ 是否是数字 """ """ S.isdigit() -> bool Return True if all characters in S are digits and there is at least one character in S, False otherwise. """ return False def islower(self): """ 是否小写 """ """ S.islower() -> bool Return True if all cased characters in S are lowercase and there is at least one cased character in S, False otherwise. """ return False def isspace(self): """ S.isspace() -> bool Return True if all characters in S are whitespace and there is at least one character in S, False otherwise. """ return False def istitle(self): """ S.istitle() -> bool Return True if S is a titlecased string and there is at least one character in S, i.e. uppercase characters may only follow uncased characters and lowercase characters only cased ones. Return False otherwise. """ return False def isupper(self): """ S.isupper() -> bool Return True if all cased characters in S are uppercase and there is at least one cased character in S, False otherwise. """ return False def join(self, iterable): """ 连接 """ """ S.join(iterable) -> string Return a string which is the concatenation of the strings in the iterable. The separator between elements is S. """ return "" def ljust(self, width, fillchar=None): """ 内容左对齐，右侧填充 """ """ S.ljust(width[, fillchar]) -> string Return S left-justified in a string of length width. Padding is done using the specified fill character (default is a space). """ return "" def lower(self): """ 变小写 """ """ S.lower() -> string Return a copy of the string S converted to lowercase. """ return "" def lstrip(self, chars=None): """ 移除左侧空白 """ """ S.lstrip([chars]) -> string or unicode Return a copy of the string S with leading whitespace removed. If chars is given and not None, remove characters in chars instead. If chars is unicode, S will be converted to unicode before stripping """ return "" def partition(self, sep): """ 分割，前，中，后三部分 """ """ S.partition(sep) -> (head, sep, tail) Search for the separator sep in S, and return the part before it, the separator itself, and the part after it. If the separator is not found, return S and two empty strings. """ pass def replace(self, old, new, count=None): """ 替换 """ """ S.replace(old, new[, count]) -> string Return a copy of string S with all occurrences of substring old replaced by new. If the optional argument count is given, only the first count occurrences are replaced. """ return "" def rfind(self, sub, start=None, end=None): """ S.rfind(sub [,start [,end]]) -> int Return the highest index in S where substring sub is found, such that sub is contained within S[start:end]. Optional arguments start and end are interpreted as in slice notation. Return -1 on failure. """ return 0 def rindex(self, sub, start=None, end=None): """ S.rindex(sub [,start [,end]]) -> int Like S.rfind() but raise ValueError when the substring is not found. """ return 0 def rjust(self, width, fillchar=None): """ S.rjust(width[, fillchar]) -> string Return S right-justified in a string of length width. Padding is done using the specified fill character (default is a space) """ return "" def rpartition(self, sep): """ S.rpartition(sep) -> (head, sep, tail) Search for the separator sep in S, starting at the end of S, and return the part before it, the separator itself, and the part after it. If the separator is not found, return two empty strings and S. """ pass def rsplit(self, sep=None, maxsplit=None): """ S.rsplit([sep [,maxsplit]]) -> list of strings Return a list of the words in the string S, using sep as the delimiter string, starting at the end of the string and working to the front. If maxsplit is given, at most maxsplit splits are done. If sep is not specified or is None, any whitespace string is a separator. """ return [] def rstrip(self, chars=None): """ S.rstrip([chars]) -> string or unicode Return a copy of the string S with trailing whitespace removed. If chars is given and not None, remove characters in chars instead. If chars is unicode, S will be converted to unicode before stripping """ return "" def split(self, sep=None, maxsplit=None): """ 分割， maxsplit最多分割几次 """ """ S.split([sep [,maxsplit]]) -> list of strings Return a list of the words in the string S, using sep as the delimiter string. If maxsplit is given, at most maxsplit splits are done. If sep is not specified or is None, any whitespace string is a separator and empty strings are removed from the result. """ return [] def splitlines(self, keepends=False): """ 根据换行分割 """ """ S.splitlines(keepends=False) -> list of strings Return a list of the lines in S, breaking at line boundaries. Line breaks are not included in the resulting list unless keepends is given and true. """ return [] def startswith(self, prefix, start=None, end=None): """ 是否起始 """ """ S.startswith(prefix[, start[, end]]) -> bool Return True if S starts with the specified prefix, False otherwise. With optional start, test S beginning at that position. With optional end, stop comparing S at that position. prefix can also be a tuple of strings to try. """ return False def strip(self, chars=None): """ 移除两段空白 """ """ S.strip([chars]) -> string or unicode Return a copy of the string S with leading and trailing whitespace removed. If chars is given and not None, remove characters in chars instead. If chars is unicode, S will be converted to unicode before stripping """ return "" def swapcase(self): """ 大写变小写，小写变大写 """ """ S.swapcase() -> string Return a copy of the string S with uppercase characters converted to lowercase and vice versa. """ return "" def title(self): """ S.title() -> string Return a titlecased version of S, i.e. words start with uppercase characters, all remaining cased characters have lowercase. """ return "" def translate(self, table, deletechars=None): """ 转换，需要先做一个对应表，最后一个表示删除字符集合 intab = "aeiou" outtab = "12345" trantab = maketrans(intab, outtab) str = "this is string example....wow!!!" print str.translate(trantab, 'xm') """ """ S.translate(table [,deletechars]) -> string Return a copy of the string S, where all characters occurring in the optional argument deletechars are removed, and the remaining characters have been mapped through the given translation table, which must be a string of length 256 or None. If the table argument is None, no translation is applied and the operation simply removes the characters in deletechars. """ return "" def upper(self): """ S.upper() -> string Return a copy of the string S converted to uppercase. """ return "" def zfill(self, width): """方法返回指定长度的字符串，原字符串右对齐，前面填充0。""" """ S.zfill(width) -> string Pad a numeric string S with zeros on the left, to fill a field of the specified width. The string S is never truncated. """ return "" def _formatter_field_name_split(self, *args, **kwargs): # real signature unknown pass def _formatter_parser(self, *args, **kwargs): # real signature unknown pass def __add__(self, y): """ x.__add__(y) <==> x+y """ pass def __contains__(self, y): """ x.__contains__(y) <==> y in x """ pass def __eq__(self, y): """ x.__eq__(y) <==> x==y """ pass def __format__(self, format_spec): """ S.__format__(format_spec) -> string Return a formatted version of S as described by format_spec. """ return "" def __getattribute__(self, name): """ x.__getattribute__('name') <==> x.name """ pass def __getitem__(self, y): """ x.__getitem__(y) <==> x[y] """ pass def __getnewargs__(self, *args, **kwargs): # real signature unknown pass def __getslice__(self, i, j): """ x.__getslice__(i, j) <==> x[i:j] Use of negative indices is not supported. """ pass def __ge__(self, y): """ x.__ge__(y) <==> x>=y """ pass def __gt__(self, y): """ x.__gt__(y) <==> x>y """ pass def __hash__(self): """ x.__hash__() <==> hash(x) """ pass def __init__(self, string=''): # known special case of str.__init__ """ str(object='') -> string Return a nice string representation of the object. If the argument is a string, the return value is the same object. # (copied from class doc) """ pass def __len__(self): """ x.__len__() <==> len(x) """ pass def __le__(self, y): """ x.__le__(y) <==> x<=y """ pass def __lt__(self, y): """ x.__lt__(y) <==> x<y """ pass def __mod__(self, y): """ x.__mod__(y) <==> x%y """ pass def __mul__(self, n): """ x.__mul__(n) <==> x*n """ pass @staticmethod # known case of __new__ def __new__(S, *more): """ T.__new__(S, ...) -> a new object with type S, a subtype of T """ pass def __ne__(self, y): """ x.__ne__(y) <==> x!=y """ pass def __repr__(self): """ x.__repr__() <==> repr(x) """ pass def __rmod__(self, y): """ x.__rmod__(y) <==> y%x """ pass def __rmul__(self, n): """ x.__rmul__(n) <==> n*x """ pass def __sizeof__(self): """ S.__sizeof__() -> size of S in memory, in bytes """ pass def __str__(self): """ x.__str__() <==> str(x) """ pass str
1.使用\转义
*\n代表换行符
pwe = 'A man,\nA plan,\nA canal.' print(pwe) A man, A plan, A canal.
*\t(tab制表符)
>>>print('a\tbc')
a bc
*使用+拼接
>>>a = 'Duck.' >>>b = 'a' >>>c = 'Grey,Duck！' >>>a+b+c Duck.Duck.Grey,Duck!
3.1、capitalize：首字母大写
def capitalize(self)
#定义一个变量a1，将字符串"alex"赋值给a1 a1 = "alex" #通过capitalize这个方法将变量a1的首字母变成大写的 ret = a1.capitalize() print(ret) Alex
3.2、cente：内容居中,width:总长度；fillchar：空白处填充内容(默认无)
def center(self,width,fillchar=None):
#定义一个变量a1，将字符串"alex"赋值给a1 a1 = "alex" #通过center这个方法将a1这个字符串居中，且ret的总长度为20，空白处用"~"填充 ret = a1.center(20,'~') print(ret)
3.3、count：子序列的个数
def count(self,sub,start=None,end=None) :
参数：
sub--这是子串，用来搜索
start--搜索从这一索引。第一个字符从0开始索引。默认情况下搜索从0开始的索引。
end--搜索从该索引结束。第一个字符从0开始的索引。默认情况下搜索结束结束的最后一个索引。
例子：
#!/usr/bin/python str = "this is string example....wow!!!"; sub = "i"; print "str.count(sub, 4, 40) : ", str.count(sub, 4, 40) sub = "wow"; print "str.count(sub) : ", str.count(sub)
结果：
str.count(sub, 4, 40) : 2 str.count(sub, 4, 40) : 1
3.4、endswith：是否以xxx结束
def endswith(self,suffix,start=None，end=None)
参数：
suffix--这可能是一个字符串或者是元组用于查后缀。
start--切片从此开始
end--切片到此为止
例子：
#!/usr/bin/python str = "this is string example....wow!!!" suffix = "wow!!!" print str.endswith(suffix) print str.endswith(suffix,20) suffix = "is" print str.endswith(suffix, 2, 4) print str.endswith(suffix, 2, 6)
结果：
True True True False
3.5、expandtabs：将tab转换成空格，默认一个tab转换成8个空格
def expandtabs(self,tabsize=None):
参数：
tabsize--指定转换字符串中的tab符号("\t")转换为空格字符串。
例子：
#!/usr/bin/python str = "this is\tstring example....wow!!!" print "Original string: " + str print "Defualt exapanded tab: " + str.expandtabs()#无参数，就还是默认的\t这么多的空格（默认是八个） print "Double exapanded tab: " + str.expandtabs(16)#16表示空格的个数是16个空格
结果：
Original string: this is string example....wow!!! Defualt exapanded tab: this is string example....wow!!! Double exapanded tab: this is string example....wow!!!
3.6、find：寻找序列位置，如果没找到，返回-1
def find(self,sub,start=None,end=None):
参数：
str--指定参与检索的字符串
start-- 开始索引，默认情况下为0
end--索引结束，默认情况下它等于字符串长度
#!/usr/bin/python str1 = "this is string example....wow!!!" str2 = "exam" print str1.find(str2) print str1.find(str2, 10)#从第十个字符开始检索 print str1.find(str2, 10,12)#从第十个开始检索，到第十二个字符结束
结果：
15 15 -1
3.7、format：字符串格式化，动态参数
def format(*args,**kwargs)
例子：
s = "hello {0},age {1}"
print(s)
#{0}、都是占位符
new1 = s.format("alex",19)
print(new1)
输出的结果：
hello {0},age {1}
hello {alex},age {19}
3.8、index：子序列的位置，如果没有找到，系统报错
def index(self,sub,start=None，end=None)
参数：
sub：指定要检索的子字符串
start：开始索引默认是0
end：结束索引默认是字符串的长度
例子：
#!/usr/bin/python str1 = "this is string example....wow!!!" str2 = "exam"; print str1.index(str2) print str1.index(str2, 10) print str1.index(str2, 40)
结果：
15 15 Traceback (most recent call last): File "test.py", line 8, in print str1.index(str2, 40); ValueError: substring not found
3.9、join表示连接
def join(self,iterable)
例子：
li = ["alex","eric"] s = "".join(li) print(li) print(s)
结果：
['alex', 'eric'] alexeric
4、列表：列表是最通用的数据类型，在Python中可以写成逗号分隔值方括号列表
创建列表
name_list = ['alex', 'seven', 'eric'] 或 name_list ＝ list(['alex', 'seven', 'eric'])
列表的基本操作
- 索引
- 切片
- 追加
- 删除
- 长度
- 切片
- 循环
- 包含
class list(object): """ list() -> new empty list list(iterable) -> new list initialized from iterable's items """ def append(self, p_object): # real signature unknown; restored from __doc__ """ L.append(object) -- append object to end """ pass def count(self, value): # real signature unknown; restored from __doc__ """ L.count(value) -> integer -- return number of occurrences of value """ return 0 def extend(self, iterable): # real signature unknown; restored from __doc__ """ L.extend(iterable) -- extend list by appending elements from the iterable """ pass def index(self, value, start=None, stop=None): # real signature unknown; restored from __doc__ """ L.index(value, [start, [stop]]) -> integer -- return first index of value. Raises ValueError if the value is not present. """ return 0 def insert(self, index, p_object): # real signature unknown; restored from __doc__ """ L.insert(index, object) -- insert object before index """ pass def pop(self, index=None): # real signature unknown; restored from __doc__ """ L.pop([index]) -> item -- remove and return item at index (default last). Raises IndexError if list is empty or index is out of range. """ pass def remove(self, value): # real signature unknown; restored from __doc__ """ L.remove(value) -- remove first occurrence of value. Raises ValueError if the value is not present. """ pass def reverse(self): # real signature unknown; restored from __doc__ """ L.reverse() -- reverse *IN PLACE* """ pass def sort(self, cmp=None, key=None, reverse=False): # real signature unknown; restored from __doc__ """ L.sort(cmp=None, key=None, reverse=False) -- stable sort *IN PLACE*; cmp(x, y) -> -1, 0, 1 """ pass def __add__(self, y): # real signature unknown; restored from __doc__ """ x.__add__(y) <==> x+y """ pass def __contains__(self, y): # real signature unknown; restored from __doc__ """ x.__contains__(y) <==> y in x """ pass def __delitem__(self, y): # real signature unknown; restored from __doc__ """ x.__delitem__(y) <==> del x[y] """ pass def __delslice__(self, i, j): # real signature unknown; restored from __doc__ """ x.__delslice__(i, j) <==> del x[i:j] Use of negative indices is not supported. """ pass def __eq__(self, y): # real signature unknown; restored from __doc__ """ x.__eq__(y) <==> x==y """ pass def __getattribute__(self, name): # real signature unknown; restored from __doc__ """ x.__getattribute__('name') <==> x.name """ pass def __getitem__(self, y): # real signature unknown; restored from __doc__ """ x.__getitem__(y) <==> x[y] """ pass def __getslice__(self, i, j): # real signature unknown; restored from __doc__ """ x.__getslice__(i, j) <==> x[i:j] Use of negative indices is not supported. """ pass def __ge__(self, y): # real signature unknown; restored from __doc__ """ x.__ge__(y) <==> x>=y """ pass def __gt__(self, y): # real signature unknown; restored from __doc__ """ x.__gt__(y) <==> x>y """ pass def __iadd__(self, y): # real signature unknown; restored from __doc__ """ x.__iadd__(y) <==> x+=y """ pass def __imul__(self, y): # real signature unknown; restored from __doc__ """ x.__imul__(y) <==> x*=y """ pass def __init__(self, seq=()): # known special case of list.__init__ """ list() -> new empty list list(iterable) -> new list initialized from iterable's items # (copied from class doc) """ pass def __iter__(self): # real signature unknown; restored from __doc__ """ x.__iter__() <==> iter(x) """ pass def __len__(self): # real signature unknown; restored from __doc__ """ x.__len__() <==> len(x) """ pass def __le__(self, y): # real signature unknown; restored from __doc__ """ x.__le__(y) <==> x<=y """ pass def __lt__(self, y): # real signature unknown; restored from __doc__ """ x.__lt__(y) <==> x<y """ pass def __mul__(self, n): # real signature unknown; restored from __doc__ """ x.__mul__(n) <==> x*n """ pass @staticmethod # known case of __new__ def __new__(S, *more): # real signature unknown; restored from __doc__ """ T.__new__(S, ...) -> a new object with type S, a subtype of T """ pass def __ne__(self, y): # real signature unknown; restored from __doc__ """ x.__ne__(y) <==> x!=y """ pass def __repr__(self): # real signature unknown; restored from __doc__ """ x.__repr__() <==> repr(x) """ pass def __reversed__(self): # real signature unknown; restored from __doc__ """ L.__reversed__() -- return a reverse iterator over the list """ pass def __rmul__(self, n): # real signature unknown; restored from __doc__ """ x.__rmul__(n) <==> n*x """ pass def __setitem__(self, i, y): # real signature unknown; restored from __doc__ """ x.__setitem__(i, y) <==> x[i]=y """ pass def __setslice__(self, i, j, y): # real signature unknown; restored from __doc__ """ x.__setslice__(i, j, y) <==> x[i:j]=y Use of negative indices is not supported. """ pass def __sizeof__(self): # real signature unknown; restored from __doc__ """ L.__sizeof__() -- size of L in memory, in bytes """ pass __hash__ = None list
4.1、append()方法用于在列表末尾添加新的对象
def append(self,p_object)
例子：
aList = [123, 'xyz', 'zara', 'abc'] aList.append( 2014 ) print "Updated List : ", aList
结果：
Updated List : [123, 'xyz', 'zara', 'abc', 2014]
4.2、ount()方法返回的value出现在列表的次数
def count(self,value)
例子：
aList = [123, 'xyz', 'zara', 'abc', 123]
print "Count for 123 : ", aList.count(123)
print "Count for zara : ", aList.count('zara')
结果：
Count for 123 : 2 Count for zara : 1
4.3、extend()方法追加序列内容到序列
def extend(self,iterzble)
例子：
aList = [123, 'xyz', 'zara', 'abc', 123]; bList = [2009, 'manni']; aList.extend(bList)把bList追加进入aList print "Extended List : ", aList ;
结果：
Extended List : [123, 'xyz', 'zara', 'abc', 123, 2009, 'manni']
4.4、index()方法返回的value出现在列表中的最低位索引
def index(self,value,start=None,end=None )
例子：
aList = [123, 'xyz', 'zara', 'abc'] print "Index for xyz : ", aList.index( 'xyz' ) print "Index for zara : ", aList.index( 'zara' )
结果：
Index for xyz : 1 Index for zara : 2
4.5、insert()方法插入对象value到表的偏移量的索引
def insert9(self,index,p_object)
index：这是要插入对象object必要的索引
p_object:这是将被插入到给定的列表中的对象
例子：
aList = [123, 'xyz', 'zara', 'abc'] aList.insert( 3, 2009) print "Final List : ", aList
结果：
Final List : [123, 'xyz', 'zara', 2009, 'abc']
4.6、pop()方法函数用于移除列表中的一个元素，默认是最后一个,返回的是从列表中移除的对象
def pop(self,index=None)
例子
aList = [123, 'xyz', 'zara', 'abc'] print "A List : ", aList.pop() print "B List : ", aList.pop(2)
结果：
A List : abc B List : zara
4.7、remove()函数用于移除列表中某一个值的第一个匹配项
def remove(self,value)
例子：
aList = [123, 'xyz', 'zara', 'abc', 'xyz']
aList.remove('xyz')
print "List : ", aList
aList.remove('abc')
print "List : ", aList
结果：
List : [123, 'zara', 'abc', 'xyz'] List : [123, 'zara', 'xyz']
4.8、reverse()函数用反向列表中的元素
def reverse(self)
例子：
aList = [123, 'xyz', 'zara', 'abc', 'xyz'] aList.reverse() print "List : ", aList
结果：
List : ['xyz', 'abc', 'zara', 'xyz', 123]
4.9、sort()函数用于对原来的列表进行排序，如果指定参数，则使用比较函数指定的比较函数
def sort(self,cmp=None,key=None )
例子：
aList = [123, 'xyz', 'ara', 'abc', 'xbz','xbc'] aList.sort() print "List : ", aList
结果：
List : [123, 'abc', 'ara', 'xbc', 'xbz', 'xyz']
5、元祖
创建元祖
ages = (11, 22, 33, 44, 55) 或 ages = tuple((11, 22, 33, 44, 55))
基本操作
- 索引
- 切片
- 循环
- 长度
- 包含
lass tuple(object): """ tuple() -> empty tuple tuple(iterable) -> tuple initialized from iterable's items If the argument is a tuple, the return value is the same object. """ def count(self, value): # real signature unknown; restored from __doc__ """ T.count(value) -> integer -- return number of occurrences of value """ return 0 def index(self, value, start=None, stop=None): # real signature unknown; restored from __doc__ """ T.index(value, [start, [stop]]) -> integer -- return first index of value. Raises ValueError if the value is not present. """ return 0 def __add__(self, y): # real signature unknown; restored from __doc__ """ x.__add__(y) <==> x+y """ pass def __contains__(self, y): # real signature unknown; restored from __doc__ """ x.__contains__(y) <==> y in x """ pass def __eq__(self, y): # real signature unknown; restored from __doc__ """ x.__eq__(y) <==> x==y """ pass def __getattribute__(self, name): # real signature unknown; restored from __doc__ """ x.__getattribute__('name') <==> x.name """ pass def __getitem__(self, y): # real signature unknown; restored from __doc__ """ x.__getitem__(y) <==> x[y] """ pass def __getnewargs__(self, *args, **kwargs): # real signature unknown pass def __getslice__(self, i, j): # real signature unknown; restored from __doc__ """ x.__getslice__(i, j) <==> x[i:j] Use of negative indices is not supported. """ pass def __ge__(self, y): # real signature unknown; restored from __doc__ """ x.__ge__(y) <==> x>=y """ pass def __gt__(self, y): # real signature unknown; restored from __doc__ """ x.__gt__(y) <==> x>y """ pass def __hash__(self): # real signature unknown; restored from __doc__ """ x.__hash__() <==> hash(x) """ pass def __init__(self, seq=()): # known special case of tuple.__init__ """ tuple() -> empty tuple tuple(iterable) -> tuple initialized from iterable's items If the argument is a tuple, the return value is the same object. # (copied from class doc) """ pass def __iter__(self): # real signature unknown; restored from __doc__ """ x.__iter__() <==> iter(x) """ pass def __len__(self): # real signature unknown; restored from __doc__ """ x.__len__() <==> len(x) """ pass def __le__(self, y): # real signature unknown; restored from __doc__ """ x.__le__(y) <==> x<=y """ pass def __lt__(self, y): # real signature unknown; restored from __doc__ """ x.__lt__(y) <==> x<y """ pass def __mul__(self, n): # real signature unknown; restored from __doc__ """ x.__mul__(n) <==> x*n """ pass @staticmethod # known case of __new__ def __new__(S, *more): # real signature unknown; restored from __doc__ """ T.__new__(S, ...) -> a new object with type S, a subtype of T """ pass def __ne__(self, y): # real signature unknown; restored from __doc__ """ x.__ne__(y) <==> x!=y """ pass def __repr__(self): # real signature unknown; restored from __doc__ """ x.__repr__() <==> repr(x) """ pass def __rmul__(self, n): # real signature unknown; restored from __doc__ """ x.__rmul__(n) <==> n*x """ pass def __sizeof__(self): # real signature unknown; restored from __doc__ """ T.__sizeof__() -- size of T in memory, in bytes """ pass tuple
具体用法：
tup1 = ('physics', 'chemistry', 1997, 2000)
tup2 = (1, 2, 3, 4, 5, 6, 7 )
5.1、索引
print(tup[1])
结果:
chemistry
5.2、len
print(len(tup1)-1)
3
5.3、切片
print(tup1[1:3])
('chemistry', 1997)
5.4、for语句
for i in tup1:
print(i)
physics
chemistry
1997
2000
5.5、删除
元组和序列一样但是唯一的不同就是元组不能改变，元组不支持删除这个功能
5.6、count 用来计算元素出现的个数
print(tup1.count('chemistry'))
1
5.7、index获取指定元素出现的索引位置（相同元素第一次出现的位置）
print(tup1.index(1997)) 3
6、字典
字典是可以变得，字典的每一个元素都是键值对
创建字典
person = {"name": "mr.wu", 'age': 18}
或
person = dict({"name": "mr.wu", 'age': 18})
常用操作：
- 索引
- 新增
- 删除
- 键、值、键值对
- 循环
- 长度
class dict(object): """ dict() -> new empty dictionary dict(mapping) -> new dictionary initialized from a mapping object's (key, value) pairs dict(iterable) -> new dictionary initialized as if via: d = {} for k, v in iterable: d[k] = v dict(**kwargs) -> new dictionary initialized with the name=value pairs in the keyword argument list. For example: dict(one=1, two=2) """ def clear(self): # real signature unknown; restored from __doc__ """ 清除内容 """ """ D.clear() -> None. Remove all items from D. """ pass def copy(self): # real signature unknown; restored from __doc__ """ 浅拷贝 """ """ D.copy() -> a shallow copy of D """ pass @staticmethod # known case def fromkeys(S, v=None): # real signature unknown; restored from __doc__ """ dict.fromkeys(S[,v]) -> New dict with keys from S and values equal to v. v defaults to None. """ pass def get(self, k, d=None): # real signature unknown; restored from __doc__ """ 根据key获取值，d是默认值 """ """ D.get(k[,d]) -> D[k] if k in D, else d. d defaults to None. """ pass def has_key(self, k): # real signature unknown; restored from __doc__ """ 是否有key """ """ D.has_key(k) -> True if D has a key k, else False """ return False def items(self): # real signature unknown; restored from __doc__ """ 所有项的列表形式 """ """ D.items() -> list of D's (key, value) pairs, as 2-tuples """ return [] def iteritems(self): # real signature unknown; restored from __doc__ """ 项可迭代 """ """ D.iteritems() -> an iterator over the (key, value) items of D """ pass def iterkeys(self): # real signature unknown; restored from __doc__ """ key可迭代 """ """ D.iterkeys() -> an iterator over the keys of D """ pass def itervalues(self): # real signature unknown; restored from __doc__ """ value可迭代 """ """ D.itervalues() -> an iterator over the values of D """ pass def keys(self): # real signature unknown; restored from __doc__ """ 所有的key列表 """ """ D.keys() -> list of D's keys """ return [] def pop(self, k, d=None): # real signature unknown; restored from __doc__ """ 获取并在字典中移除 """ """ D.pop(k[,d]) -> v, remove specified key and return the corresponding value. If key is not found, d is returned if given, otherwise KeyError is raised """ pass def popitem(self): # real signature unknown; restored from __doc__ """ 获取并在字典中移除 """ """ D.popitem() -> (k, v), remove and return some (key, value) pair as a 2-tuple; but raise KeyError if D is empty. """ pass def setdefault(self, k, d=None): # real signature unknown; restored from __doc__ """ 如果key不存在，则创建，如果存在，则返回已存在的值且不修改 """ """ D.setdefault(k[,d]) -> D.get(k,d), also set D[k]=d if k not in D """ pass def update(self, E=None, **F): # known special case of dict.update """ 更新 {'name':'alex', 'age': 18000} [('name','sbsbsb'),] """ """ D.update([E, ]**F) -> None. Update D from dict/iterable E and F. If E present and has a .keys() method, does: for k in E: D[k] = E[k] If E present and lacks .keys() method, does: for (k, v) in E: D[k] = v In either case, this is followed by: for k in F: D[k] = F[k] """ pass def values(self): # real signature unknown; restored from __doc__ """ 所有的值 """ """ D.values() -> list of D's values """ return [] def viewitems(self): # real signature unknown; restored from __doc__ """ 所有项，只是将内容保存至view对象中 """ """ D.viewitems() -> a set-like object providing a view on D's items """ pass def viewkeys(self): # real signature unknown; restored from __doc__ """ D.viewkeys() -> a set-like object providing a view on D's keys """ pass def viewvalues(self): # real signature unknown; restored from __doc__ """ D.viewvalues() -> an object providing a view on D's values """ pass def __cmp__(self, y): # real signature unknown; restored from __doc__ """ x.__cmp__(y) <==> cmp(x,y) """ pass def __contains__(self, k): # real signature unknown; restored from __doc__ """ D.__contains__(k) -> True if D has a key k, else False """ return False def __delitem__(self, y): # real signature unknown; restored from __doc__ """ x.__delitem__(y) <==> del x[y] """ pass def __eq__(self, y): # real signature unknown; restored from __doc__ """ x.__eq__(y) <==> x==y """ pass def __getattribute__(self, name): # real signature unknown; restored from __doc__ """ x.__getattribute__('name') <==> x.name """ pass def __getitem__(self, y): # real signature unknown; restored from __doc__ """ x.__getitem__(y) <==> x[y] """ pass def __ge__(self, y): # real signature unknown; restored from __doc__ """ x.__ge__(y) <==> x>=y """ pass def __gt__(self, y): # real signature unknown; restored from __doc__ """ x.__gt__(y) <==> x>y """ pass def __init__(self, seq=None, **kwargs): # known special case of dict.__init__ """ dict() -> new empty dictionary dict(mapping) -> new dictionary initialized from a mapping object's (key, value) pairs dict(iterable) -> new dictionary initialized as if via: d = {} for k, v in iterable: d[k] = v dict(**kwargs) -> new dictionary initialized with the name=value pairs in the keyword argument list. For example: dict(one=1, two=2) # (copied from class doc) """ pass def __iter__(self): # real signature unknown; restored from __doc__ """ x.__iter__() <==> iter(x) """ pass def __len__(self): # real signature unknown; restored from __doc__ """ x.__len__() <==> len(x) """ pass def __le__(self, y): # real signature unknown; restored from __doc__ """ x.__le__(y) <==> x<=y """ pass def __lt__(self, y): # real signature unknown; restored from __doc__ """ x.__lt__(y) <==> x<y """ pass @staticmethod # known case of __new__ def __new__(S, *more): # real signature unknown; restored from __doc__ """ T.__new__(S, ...) -> a new object with type S, a subtype of T """ pass def __ne__(self, y): # real signature unknown; restored from __doc__ """ x.__ne__(y) <==> x!=y """ pass def __repr__(self): # real signature unknown; restored from __doc__ """ x.__repr__() <==> repr(x) """ pass def __setitem__(self, i, y): # real signature unknown; restored from __doc__ """ x.__setitem__(i, y) <==> x[i]=y """ pass def __sizeof__(self): # real signature unknown; restored from __doc__ """ D.__sizeof__() -> size of D in memory, in bytes """ pass __hash__ = None dict
dict = {'Name': 'Zara', 'Age': 7, 'Name1': 'Manni'}
6.1索引
print(dict['Name']) #索引都是key
Zara
6.2循环，默认输出key
dict = {'Name': 'Zara', 'Age': 7, 'Name1': 'Manni','sex':'M','Abe':'ws','Abf':'wsf'};
#print(dict['Name'])
for i in dict:
print(i)
结果：
Abe Abf Age sex Name1 Name
6.3获取所有的键
dict = {'Name': 'Zara', 'Age': 7, 'Name1': 'Manni','sex':'M','Abe':'ws','Abf':'wsf'};
print(dict.keys())
['Abe', 'Abf', 'Age', 'sex', 'Name1', 'Name']
6.4获取所有的键值
dict = {'Name': 'Zara', 'Age': 7, 'Name1': 'Manni','sex':'M','Abe':'ws','Abf':'wsf'};
print(dict.values())
6.5字典中的删除功能
dict = {'Name': 'Zara', 'Age': 7, 'Class': 'First'};
del dict['Name']; # remove entry with key 'Name'
dict.clear(); # remove all entries in dict
del dict ; # delete entire dictionary
print "dict['Age']: ", dict['Age'];
print "dict['School']: ", dict['School'];
结果：
dict['Age']:
Traceback (most recent call last):
File "test.py", line 8, in <module>
print "dict['Age']: ", dict['Age'];
TypeError: 'type' object is unsubscriptable
注：经过del dict删除，字典已经不存在了
6.6get()方法返回给定键的值，如果键不可用，则返回默认值None
dict.get(key,defaylt=None)
key:这是要搜索存在于字典中的键
default：这是要返回键不存在的情况下默认值
例子：
dict = {'Name': 'Zara', 'Age': 27}
print "Value : %s" % dict.get('Age')
print "Value : %s" % dict.get('Sex')
结果：
Value : 27 Value : None
6.7、has_key：如果给定的键在字典中可用，has_key()返回true，否则是false
dict.has_key(key)
例子：
dict = {'Name': 'Zara', 'Age': 7}
print "Value : %s" % dict.has_key('Age')
print "Value : %s" % dict.has_key('Sex')
结果：
Value : True Value : False
6.8、item()方法返回字典的(键，值)元组对的列表
dict.item()
例子：
dict = {'Name': 'Zara', 'Age': 7}
print "Value : %s" % dict.items()
结果：
Value : [('Age', 7), ('Name', 'Zara')]
其他：
1、for循环：用户按照循环可迭代对象中的内容
li = [11,22,33,44]
for item in li:
print item
结果：
11 22 33 44
2、enumrate为可以迭代的对象添加序号
li = [11,22,33]
for k,v in enumerate(li, 1):#1表示从1开始编号
print(k,v)
结果：
(1, 11) (2, 22) (3, 33)
3、range和xrange(在3.0以上的版本已经没有了)
print range(1, 10) # 结果：[1, 2, 3, 4, 5, 6, 7, 8, 9] print range(1, 10, 2) # 结果：[1, 3, 5, 7, 9] print range(30, 0, -2) # 结果：[30, 28, 26, 24, 22, 20, 18, 16, 14, 12, 10, 8, 6, 4, 2]
作业：
一、元素分类
有如下值集合 [11,22,33,44,55,66,77,88,99,90...]，将所有大于 66 的值保存至字典的第一个key中，将小于 66 的值保存至第二个key的值中。
即： {'k1': 大于66的所有值, 'k2': 小于66的所有值}
dict = {'k1':[],'k2':[]}
li = [11,22,33,44,55,66,77,88,99,90]
for i in li:#检索li列表中的元素
#print(i)
if i >= 66:
#print(i)
dict['k1'].append(i)#将i追加到k1的值中
else:
#print(i)
dict['k2'].append(i)
print(dict)
二、查找
查找列表中元素，移除每个元素的空格，并查找以 a或A开头 并且以 c 结尾的所有元素。
li = ["alec", " aric", "Alex", "Tony", "rain"]
tu = ("alec", " aric", "Alex", "Tony", "rain")
dic = {'k1': "alex", 'k2': ' aric', "k3": "Alex", "k4": "Tony"}
for i in li: #print(i) #s5 = i.strip() # print(s5) # s4 = s5.capitalize() s4 = i.strip().capitalize() #print(s4) #print(s4[:1]) if s4[:1] == 'A' and s4[-1] == 'c': # s6 = s4.[0] print(s4) tu = ("alec", " aric", "Alex", "Tony", "rain") for i in tu: #print(i) s4 = i.strip().capitalize() #print(s4) if s4[0] == 'A' and s4[-1] == 'c': print(s4) dic = {'k1': "alex", 'k2': ' aric', "k3": "Alex", "k4": "Tony"} # for key,item in dic: # print(key,item) tu1 = dic.values() #print (tu1) for i in tu1: s4 = i.strip().capitalize() if s4[0] == 'A' and s4[-1] == 'c': print(s4)
三、输出商品列表，用户输入序号，显示用户选中的商品
li = ["手机", "电脑", '鼠标垫', '游艇']
li = ["手机", "电脑", '鼠标垫', '游艇'] for i in li: print(i) inp = input("请输入商品：") print(inp) li = ["手机", "电脑", '鼠标垫', '游艇'] for k,item in enumerate(li): print(k,item) inp = input("请输入商品：") inp_num = int(inp) print(li[inp_num])
四、购物车
预习的内容
