python 内置函数filter
发布时间:2020-12-17 08:20:54 所属栏目:Python 来源:网络整理
导读:python 内置函数filter class filter(object): """ filter(function or None,iterable) -- filter object Return an iterator yielding those items of iterable for which function(item) is true. If function is None,return the items that are true. ""
python 内置函数filter class filter(object): """ filter(function or None,iterable) --> filter object Return an iterator yielding those items of iterable for which function(item) is true. If function is None,return the items that are true. """ filter(func,iterator) func:自定义或匿名函数中所得值是布尔值,true将保留函数所取到的值,false则取反。 例: 过滤列表['text_test_text','test_text_1','text_test_2','3_test_text','test_test'] s.rfind'text'+1 Python3中 rfind() 返回字符串最后一次出现的位置,如果没有匹配项则返回-1。 # Filter li = ['text_test_text','test_test'] # 默认保留函数所取到的值 print(list(filter(lambda s: s.rfind('text') + 1,li))) # 取反,下三个例子是一样的 print(list(filter(lambda s: not s.rfind('text') + 1,li))) # Noe 自定义函数 l1 = ['text_test_text','test_test'] def distinguish(l): nl = [] for s in l: if s.rfind("text") + 1: nl.append(s) return nl print(distinguish(l1)) # Two 自定义高阶函数 l2 = ['text_test_text','test_test'] def f(s): return s.rfind('text') + 1 def distinguish(func,array): nl = [] for s in array: if func(s): nl.append(s) return nl print(distinguish(f,l2)) # Three 匿名函数 l3 = ['text_test_text','test_test'] def distinguish(func,array): nl = [] for s in array: if func(s): nl.append(s) return nl print(distinguish(lambda s: s.rfind('text') + 1,l3)) 感谢阅读,希望能帮助到大家,谢谢大家对本站的支持! (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |