2014-10-17

Erlang标准库示例 lists

keysearch(Key, N, TupleList) -> {value, Tuple} | false

Types:

Key = term()
N = integer() >= 1
1..tuple_size(Tuple)
TupleList = [Tuple]
Tuple = tuple()

在一个元组列表中搜索, 列表中元组的第N个元素等于Key时返回 {value, Tuple},其中Tuple为找到的这个元组. 如果没有找到返回false.

Note
该函数的保留是为了兼容, 使用lists:keyfind/3(R13A引入的一个方法)更加方便.

例子

lists:keysearch/3

1> lists:keysearch(mail,1, [{username, "13012345678"}, {mail, "13012345678@139.com"}, {tel, 13012345678}]).
{value,{mail,"13012345678@139.com"}}

lists:keyfind/3

3> lists:keyfind(mail,1, [{username, "13012345678"}, {mail, "13012345678@139.com"}, {tel, 13012345678}]).
{mail,"13012345678@139.com"}

注意lists:keysearch/3和lists:keyfind/3返回值的差异.

Erlang

lists