python推导式

• 列表(list)推导式：返回一个list

[out_exp_res for out_exp in input_list] [out_exp_res for out_exp in
input_list if condition]

• 字典(dict)推导式: 返回一个dict

{ key_expr: value_expr for value in collection }
{ key_expr: value_expr for value in collection if condition }

• 集合(set)推导式:返回一个set

{ expression for item in Sequence } { expression for item in Sequence
if conditional }

• 元组(tuple)推导式: 返回一个tuple

(expression for item in Sequence ) (expression for item in Sequence
if conditional )

字典的内置函数和操作方法
lien=http://t.csdn.cn/bvZrI