Python中min/max函数的用法

本篇以min()函数为例进行说明，max()同理。

先来看看源码

def min(*args, key=None): # known special case of min
    """
    min(iterable, *[, default=obj, key=func]) -> value
    min(arg1, arg2, *args, *[, key=func]) -> value
    
    With a single iterable argument, return its smallest item. The
    default keyword-only argument specifies an object to return if
    the provided iterable is empty.
    With two or more arguments, return the smallest argument.
    """
    pass

用法一：

# 常规用法,对可迭代对象求最小值

a = min(1, 2, 3)
print(a)

b = [1, 2, 3]
res = min(b)
print(res)

用法二:

# 当第二参数key不为空时,以key的函数对象为依据进行判断

a = [1, 2, 3, -4]
res1 = min(a)
res2 = min(a, key=lambda x: abs(x))
print(res1)
print(res2)

# 输出结果
-4
1

用法三:

# 对字典进行数据操作时,默认只会对kye,而不是value,
#若是想求得字典中值最大的那组数据需要先用zip函数进行翻转
dict = {1: 'c', 2: 'b', 3: 'a'}
min_dict1 = min(dict)
min_dict = min(zip(dict.values(), dict.keys()))
print(min_dict1)
print(min_dict)

# 输出结果
1
('a', 3)

对于翻转后的字典键值对,当键(原来的值)相等时才会对比值(原来的键)