Python数据类型转换汇总

# coding:utf-8:

if __name__ == '__main__':
   a = 1.56
    print(int(a))  # 1
    b = 1
    print(float(b))  # 1.0

# coding:utf-8:

if __name__ == '__main__':
    a = '123'
    print(int(a))  # 123
    # print(int('123.0')) Error
    # print(int('a123')) Error
    b = 123
    print(type(str(b)))  # <class 'str'>

# coding:utf-8:

if __name__ == '__main__':

   
    a = 123.0
    print(type(str(a)))  # <class 'str'>

    a = '123.01'
    print(float(a))  # 123.01
    # print(float('123.01.1')) Error
    print(float('.123'))  # 0.123
    print(float('123.'))  # 123.0
    print(float('123'))  # 123.0

# coding:utf-8:

if __name__ == '__main__':
    '''
    例1:list(string)能将字符串一个字符一个字符的切割为列表
        string.join(list)能将list每一个元素之间以string相拼接形成字符串
    例2:string.split(sep=None,max_split = -1) 按照指定字符和切割次数将字符串变成list
        sep:切割符，默认切空格
        max_split:切割次数 默认-1代表无限制，切完为止
    '''
    # 例1
    print(list('abc'))  # ['a', 'b', 'c']
    print(''.join(['a', 'b', 'c']))  # 'abc'
    print(','.join(['a', 'b', 'c']))  # 'a,b,c'

    # 例2
    print('a,b,c'.split(',', 1))  # ['a', 'b,c']
    print('a,b,c'.split(','))  # ['a', 'b', 'c']
    print('a b c'.split())  # ['a', 'b', 'c']

# coding:utf-8:

if __name__ == '__main__':
    '''
    例1:string转tuple使用tuple(string):得到的tuple由字符串的每一个字符构成
        tuple不能直接转成string:可以先转list，后转string
    '''
    # 例1
    string = '12344'
    t = tuple(string)
    print(t)  # ('1', '2', '3', '4', '4')
    print(''.join(list(t)))  # '12344'

# coding:utf-8:

if __name__ == '__main__':
    '''
    例1:list转tuple使用tuple(list)
        tuple转list使用list(tuple)
    '''

    # 例1
    a = ['a', 'b', 'c']
    t = tuple(a)
    print(t)  # ['a', 'b', 'c']
    l = list(t)
    print(l)  # ['a', 'b', 'c']

# coding:utf-8:

if __name__ == '__main__':
    '''
    例1:None,0,空字符串，空list,空tuple,空dict，空set都能转成False，其它都能转成True
    '''

    # 例1
    a = 1
    print(bool(a))  # True
    print(bool(2))  # True
    print(bool(0))  # False
    print(bool(None))  # False
    print(bool([]))  # False
    print(bool([1]))  # True
    print(bool(set()))  # False
    print(bool(set('1')))  # True
    print(bool({}))  # False
    print(bool({'name': 'xie'}))  # True
    print(bool(''))  # False
    print(bool(' '))  # True
    print(bool('0'))  # True
    print(bool('False'))  # True

# coding:utf-8:

if __name__ == '__main__':
    '''
    例1:bool转int:True=>1,False=>0
    例2:bool转float:True=>1.0,False=>0.0
    例3:bool转string:True=>'True',False=>'False'
    '''

    a = True
    b = False

    # 例1
    print(int(a))  # 1
    print(int(b))  # 0

    # 例2
    print(float(a))  # 1.0
    print(float(b))  # 0.0

    # 例3
    print(str(a))  # 'True'
    print(str(b))  # 'False'