Python filter() function

作用

filter（）方法通过测试序列中每个元素是否为真的函数来过滤给定的序列。

语法

filter(function, sequence)

Example 1: 过滤list 值

def fun(variable):
    letters = ['a', 'e', 'i', 'o', 'u']
    if (variable in letters):
        return True
    else:
        return False
  
  
# sequence
sequence = ['g', 'e', 'e', 'j', 'k', 's', 'p', 'r']
  
# using filter function
filtered = filter(fun, sequence)
  
print('The filtered letters are:')
for s in filtered:
    print(s)

Example 2: 结合lambda 表达式

seq = [0, 1, 2, 3, 5, 8, 13]
 
result = filter(lambda x: x % 2 != 0, seq)
result = filter(lambda x: x % 2 == 0, seq)

参考：

https://www.geeksforgeeks.org/filter-in-python/