python基本数据类型-----int, str, list, tuple, dict, bool

数字  int

(1)int 转换：

a = "123"
b = int(a)
print(b)

输出： 123

num = "0011"
v = int(num, base=2)
print(v)

输出： 3

age = 5
r = age.bit.length()
print(r)

输出： 3 表示至少需要的二进制位数5是101

 

字符串 str

 （1）center() 字符串居中

  test = "alex"

  v = test.center(20, "*")

  print(v)

输出： ********alex******** 

（2）count() 某字符串出现的次数计数
test = "alexalexr"
v = test.count("ex", start, end)
print(v)

输出： 1 or 2 or 0  当设置不同的起始位置，会的到不同的结果。

(3)endswith()以什么结尾

test = "alex"
v = test.endswith('ex')
print(v)

输出： True

(4)find() 从开始找某字符串返回下标
test = "alexalex"
v = test.find('ex', start, end)
print(v)
输出： 2

(5)format() 占位符，将一个字符串中的占位符替换成指定的值
test = "i am {name},{age}"
print(test)
v = test.format(name = 'alex', age =19)
print(v)
输出： 
i am {name},{age}
i am alex,19

test = "i am {0},{1}"
print(test)
v = test.format('alex' ,19)
print(v)
输出： 
i am {0},{1}
i am alex,19

(6)format_map() 将一个字符串中的占位符替换成指定的值,传入的值：{"name" : 'alex', "a" : 19}

test = "i am {name}, age {a}"
print(test)
v = test.format_map({"name" : 'alex', "a" : 19})
print(v)
输出： 
i am {name}, age {a}
i am alex, age 19

(7)isalum() 判断字符串中是否只是数字和字母
test01 = "123_nnjs"
test02 = "123jjs"
v1 = test01.isalum()
v2 = test02.isalum()
print(v1 ,v2)
输出： False ,True

(8)expandtabs(),断句20
test ="username\temail\tpassword\nlaiying\tying@q.com\t123\nlaiying\tying@q.com\t123\nlaiying\tying@q.com\t123"
v = test.expandtabs(20)
print(v)

输出：
username email password
laiying ying@q.com 123
laiying ying@q.com 123
laiying ying@q.com 123

(9) join() ,将字符串中的每一个元素按照指定分隔符进行拼接
test = "你是风儿我是沙"
print(test)
v = "_".join(test)
print(v)

输出：
你是风儿我是沙
你_是_风_儿_我_是_沙

 

(10)ljust(), rjust()指定字符长度，指定用特定符号补充

test = "alex"
v = test.ljust(20, "*")
print(v)
# 输出：
# alex****************

test = "alex"
v = test.rjust(20, "*")
print(v)
# 输出：
# ****************alex

(11) low(), islow(),小写转换与判断
test = "Alex"
v1 = test.islower()
v2 = test.lower()
print(v1, v2)

# 输出：False alex

(12) upper(), isupper(),大写转换与判断
test = "Alex"
v1 = test.isupper()
v2 = test.upper()
print(v1, v2)

# 输出：False ALEX

(13) lstrip(), rstrip(), strip()默认去空格，\n,\t；加参数可以指定去除某个字符串
test = "   alex   "
v1 = test.lstrip() # 去左边空格
v2 = test.rstrip() # 去右边空格
v3 = test.strip() # 去空格
print(v1,v2,v3)

# 输出：alex

(14) partition() , rpartition(), split(), rsplit()以指定字符串分割
test = "testkstkawlked"
v1 = test.partition("st")
v2 = test.rpartition("st")
v3 = test.split("st")
v4 = test.rsplit("st")
print(v1, type(v1))  # 输出： ('te', 'st', 'kstkawlked') <class 'tuple'>
print(v2, type(v2))  # 输出：('testk', 'st', 'kawlked') <class 'tuple'>
print(v3, type(v3))  # 输出：['te', 'k', 'kawlked'] <class 'list'> 没获取到分割的当前字符"st"
print(v4, type(v4))  # 输出：['te', 'k', 'kawlked'] <class 'list'>

""" 输出：
    ('te', 'st', 'kstkawlked') <class 'tuple'>  
    ('testk', 'st', 'kawlked') <class 'tuple'>
    ['te', 'k', 'kawlked'] <class 'list'> 没获取到分割的当前字符"st"
    ['te', 'k', 'kawlked'] <class 'list'>
"""

(15)splitlines(), 参数True或False: 是否保留换行符

test = "lskdfie\nksjkd\nksdkfow"
v = test.splitlines(True)
v1 = test.splitlines(False)
print(v, v1)
# 输出：
#     ['lskdfie\n', 'ksjkd\n', 'ksdkfow']
#     ['lskdfie', 'ksjkd', 'ksdkfow']

(16)索引，下标，切片, 
test = "ksielw"
v = test[0:3]  # 不包含index=3
v1 = test[0:-1]
v2 = test[0:]
print(test[0])
print(v)
print(v1)
print(v2)

"""
输出：
    k
    ksi
    ksiel
    ksielw
"""
(17) replace(a1,a2,a3) 用a2替换a1, 默认替换完全，a3是替换的个数
test = "alexalexalex"
v = test.replace("ex","ss")
v1 = test.replace("ex","ss",2)

print(v)
print(v1)

# 输出： alssalssalss， alssalssalex

(18)range(0, 100, 5)获得0~99的数字，5是步长r = range(0,10)
print(r) # 输出：range(0, 10)
for i in r:
    print(str(i)+"-", end="")
"""
输出：
0-1-2-3-4-5-6-7-8-9-
"""

test = "alex"
l = range(0, len(test))
for i in l:
    print(i, test[i])
"""
输出：
0 a
1 l
2 e
3 x
"""

(19)isnumeric(),isdigit()，isdecimal()，数字判断，经常用 isdecimal()

test1 = "二"
test2 = "②" 
test3 = "2" 
v1 = test1.isnumeric() 
v2= test2.isnumeric() 
v3 = test3.isnumeric() 
print (v1,v2,v3) 
输出： True True True

v1 = test1.isdigit()
v2 = test2.isdigit()
v3 = test3.isdigit()
print (v1,v2,v3)
输出：
False True True

v1 = test1.isdecimal()
v2 = test2.isdecimal()
v3 = test3.isdecimal()
print (v1,v2,v3)
输出：
False False True 

(20)isprintable()是否存在不可显示的字符 
# \t 制表符 
# \n 换行 
test = "oiuas\tdfkj" 
v = test.isprintable() 
print(v)

输出：False

 

列表  list

元组 tuple

字典 dict

布尔值 bool