python中的map函数

 def f(x):
     return x * x

 """将一个全是数字的list变成平方形式"""

 def f2():
     ls = [1, 2, 3, 4, 5]
     r2 = map(f, ls)
     print(list(r2))

 """将list的值均变为字符串"""

 def str2():
     ls = ['a', 2, 3, 4, 5]
     ls2 = map(str, ls)
     print(ls2)
     print(list(ls2))

 """将一个list里的首字母大写,后续字母小写"""

 def format_name(s):
     s1 = s[0:1].upper() + s[1:].lower()
     return s1

 def slower():
     L = ['jiyanjiao', 'jiyanjiao', 'jiyanjiao', 'jiyanjiao']
     m = 0
     for i in L:
         L[m] = i[0:1].upper() + i[1:]
         m = m + 1
     for index, name in enumerate(L):
         print(index, '-', name)
         # enumerate() 函数用于将一个可遍历的数据对象(如列表、元组或字符串)组合为一个索引序列，同时列出数据和数据下标，一般用在 for
         # 循环当中。

 f2()
 str2()
 slower()

 """打印结果
 [1, 4, 9, 16, 25]
 <map object at 0x0000018601F31390>
 ['a', '2', '3', '4', '5']
 0 - Jiyanjiao
 1 - Jiyanjiao
 2 - Jiyanjiao
 3 - Jiyanjiao

 """