python 内置方法

python 内置函数

1. abs()

abs(x)
    Return the absolute value of a number. The argument may be an integer or a floating point number. If the argument is a complex number, its magnitude is returned.
# 返回一个数的绝对值，如果是复数，则返回它的大小

>>> number2 = -12.02
>>> print(abs(number2))
12.02
>>> number1 = 12
>>> print(abs(number1))
12

2. all(iterable)

# Return True if all elements of the iterable are true (or if the iterable is empty). Equivalent to:
    def all(iterable):
        for element in iterable:
            if not element:
                return False
        return True
# 字面翻译，判断一个迭代器是否存在空值，如果存在空值，则为FALSE。类似与条件判断符号 AND， 全真才为真。

#!/usr/bin/env python
# -*- coding:utf-8 -*- 

if __name__ == '__main__':
    'functions is test all() '
    list1 = list(range(10))
    'append space in list1'
    list1.append("")
    'print it'
    for x in list1:
        print(x)
    temp = all(list1)
    if temp:
        print("这个列表没有 空值")
    else:
        print("这个列表存在空值")

3. any(iterable)

  

# Return True if any element of the iterable is true. If the iterable is empty, return False. Equivalent to:
    def any(iterable):
        for element in iterable:
            if element:
                return True
        return False
# 判断 一个迭代器中是否存在真值，如果存在，则返回 True， 类似与条件判断符号 OR

#!/usr/bin/env python
# -*- coding:utf-8 -*- 

if __name__ == '__main__':
    'functions is test any() '
    'number1 是 集合类型'
    number1 = set()
    temp1 = any(number1)
    if temp1:
        print("数据已清空，还没有更新")
    else:
        number1.add('The Book is important ! ')
        print(number1) 

 4. bool()

class bool([x])

    Return a Boolean value, i.e. one of True or False. x is converted using the standard truth testing procedure. If x is false or omitted, this returns False; otherwise it returns True. 
The bool class is a subclass of int (see Numeric Types — int, float, complex). It cannot be subclassed further. Its only instances are False and True (see Boolean Values).
# 判断 一个参数的真假，一般是 NONE，{}，[],0，"" 为假。  

#!/usr/bin/env python
# -*- coding:utf-8 -*- 

if __name__ == '__main__':
    'functions is test bool()'
    string1 = input(prompt='Please your zhanghao:')
    if bool(string1):
        print('The zhanghao is %s' % string1)
    else:
        print('Please your zhanghao:')

5. bytes()

 class bytes([source[, encoding[, errors]]])
    Return a new “bytes” object, which is an immutable sequence of integers in the range 0 <= x < 256. bytes is an immutable version of bytearray – it has the same non-mutating methods and the same indexing and slicing behavior.