num = 100
num2 = "100"
name = "laowang"
int(num2)
str(num)
len(name) #7
a = "lao"
b = "wang"
c = "zhao"
d = a+b #d "laowang"
A = 100
B = 200
C = A+B #C 300
e = "==="+a+b+"==="
f = "===%s==="%(a+b)
下标:
name = "abcdef"
name[2] # "c"
name[0] # "a"
name [1] # "b"
name[9] # string index out of range 越界
len(name) # 6
name[len(name) - 1] # "f"
name[-1] #"f"
name[-2] #"e"
name[-3] #"d"
切片:
name = "abcdefABCDEF"
name[2:5] # "cde"
name[2:6] # "cdef"
name[2:-2] # "cdefABCD"
name[2:-1] # "cdefABCDE"
name[2:0] # ""
name[2:] # "cdefABCDEF"
name[2:-1:2] # "ceACE"
name[2:-1:1] # "cdefABCDE"
name[起始位置:终止为止:步长]
逆序:
name[0:] # "abcdefABCDEF"
name[-1:] # "F"
name[-1:0] # ""
name[-1:0:-1] # "FEDCBAfedcb"
name[-1::-1] # "FEDCBAfedcba"
name[::-1] # "FEDCBAfedcba"
字符串的常见操作:
myStr = "hello world itcast and itcastxxxcpp"
myStr.
myStr.find("world") # 6 表示字符串在原字符串的下标
myStr.find("dongge") # -1
myStr.find("itcast") # 12
myStr.rfind("itcast") # 23
myStr.index("world") # 6
myStr.index("donge") # 产生异常
myStr.rindex("itcast") # 23
myStr.count("world") # 1
myStr.count("itcast") # 2
myStr.count("XXXX") # 0
替换:
myStr.replace("world","WORLD") # "hello WORLD itcast and itcastxxxcpp"
myStr.replace("itcast","xxx") # "hello world xxx and xxxxxxcpp"
myStr.replace("itcast","xxx",1) # "hello world xxx and itcastxxxcpp"
myStr.split(" ") # ["hello","world","itcast","and","itcastxxxcpp"]
myStr.capitalize() # "Hello world itcast and itcastxxxcpp"
myStr.title() # "Hello World Itcast And Itcastxxxcpp"
myStr = "hello world\titcast"
myStr.split() # ["hello","world","itcast"]
file_name = "xxxx.txt"
file_name.endswith(".txt") # True 判断是否结尾
name = "wang xxxx"
name.startswith("wang") # True 判断是否开头
myStr.lower() # 转换myStr中所有大写字符为小写
myStr.upper() # 转换myStr中的小写字母为大写
lyric = "想要陪你一起看大海"
lyric.center(50) # " 想要陪你一起看大海 "
lyric.ljust(50) # "想要陪你一起看大海 "
lyric.rljust(50) # " 想要陪你一起看大海"
test = lyric.center(50) # " 想要陪你一起看大海 "
test.lstrip() # "想要陪你一起看大海 "
test.rstrip() # " 想要陪你一起看大海"
test.strip() # "想要陪你一起看大海"
myStr.partition("itcast") # ('hello world','itcast',' and itcastxxxcpp') 元组 从左边找到第一个开始分
myStr.partition("itcast") # ('hello world itcast and ','itcast','xxxcpp') 元组 从右边找到第一个开始分
test = "hello\nworld\nxxx\nyy\nzz"
test.splitlines() # ['hello','world','xxx','yy','zz'] 按行分割
num = input("请输入一个选项(1-6):")
请输入一个选项(1-6):q
if num.isalpha():
print("是纯字母")
if num.isdigit():
print("是纯数字")
if num.isalnum()
print("是字母或数字或组合")
if num.isspace()
print("是纯空格")
a = ["aaa","bbb","ccc"]
b = "="
b.join(a) # 'aaa=bbb=ccc'
b = " "
b.join(a) # 'aaa bbb ccc'