October 2022
Beginner to intermediate
390 pages
7h 5m
Chinese
Content preview from Perl语言入门（第8版）
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列表与数组
｜
65
们将会看到如何按自定规则排序。
sort
操作符只负责读取某个列表，对它排序，继而
返回排序后的新列表。来看几个例子：
@rocks = qw/ bedrock slate rubble granite /;
@sorted = sort(@rocks); #
返回
bedrock, granite, rubble, slate
@back = reverse sort @rocks; #
逆序，从
slate
到
bedrock
排列
@rocks = sort @rocks; #
将排序后的结果存到原数组
@rocks
@numbers = sort 97..102; #
得到
100, 101, 102, 97, 98, 99
从最后一个例子可以看出，将数字当成字符串来排序，这样的结果显然不对。按默认
排序规则，任何以
1
开头的字符串会被排在以
9
开头的字符串之前。此外，排序操作
和
reverse
操作一样，不会修改原始参数，只是返回新的列表。所以要对数组排序，
就必须将排序后的结果存回数组：
sort @rocks; #
错误，这不会修改
@rocks
@rocks = sort @rocks; #
现在收集到的石头从小到大排好了
each
操作符
从
Perl 5.12
开始，已经可以针对数组使用
each
操作符了。但在此之前，
each
只能用
于提取哈希的键－值对，有关哈希的内容我们留到第
6
章再讲。
每次对数组调用
each
，会返回数组中下一个元素对应的两个值——数组索引与元素 ...
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.