I have a string
我有一个字符串
my $foo = 'one#two#three!four#five#six';
from which I want to extract the parts that are seperated by either a # or a !. This is easy enough with split:
从中我想要提取由#或a!分隔的部分。拆分时这很容易:
my @parts = split /#|!/, $foo;
An additional requirement is that I also need to capture the exclamation marks. So I tried
另外一个要求是我还需要捕获感叹号。所以我试过了
my @parts = split /#|(!)/, $foo;
This however returns either an undef value or the exclamation mark (which is also clearly stated in the specification of split).
然而,这会返回undef值或感叹号(在拆分规范中也明确说明)。
So, I weed out the unwanted undef values with grep:
所以,我用grep清除了不需要的undef值:
my @parts = grep { defined } split /#|(!)/, $foo;
This does what I want.
这就是我想要的。
Yet I was wondering if I can change the regular expression in a way so that I don't have to also invoke grep.
然而,我想知道我是否可以以某种方式更改正则表达式,以便我不必也调用grep。
2 个解决方案
#1
5
When you use split, you may not omit the empty captures once a match is found (as there are always as many captures in the match as there are defined in the regular expression). You may use a matching approach here, though:
当您使用split时,一旦找到匹配项,您可能不会省略空捕获(因为匹配中的捕获总是与正则表达式中定义的一样多)。不过,您可以在此处使用匹配方法:
my @parts = $foo =~ /[^!#]+|!/g;
This way, you will match 1 or more chars other than ! and # (with [^!#]+ alternative), or an exclamation mark, multiple times (/g).
这样,您将匹配除1之外的1个或更多字符!和#(带[^!#] +替代)或感叹号,多次(/ g)。
#2
2
Use "empty string followed by an exclamation mark or empty string preceded by an exclamation mark" in place of your second alternative:
使用“空字符串后跟感叹号或带有感叹号的空字符串”代替您的第二个备选方案:
my @parts = split /#|(?=!)|(?<=!)/, $foo;
#1
5
When you use split, you may not omit the empty captures once a match is found (as there are always as many captures in the match as there are defined in the regular expression). You may use a matching approach here, though:
当您使用split时,一旦找到匹配项,您可能不会省略空捕获(因为匹配中的捕获总是与正则表达式中定义的一样多)。不过,您可以在此处使用匹配方法:
my @parts = $foo =~ /[^!#]+|!/g;
This way, you will match 1 or more chars other than ! and # (with [^!#]+ alternative), or an exclamation mark, multiple times (/g).
这样,您将匹配除1之外的1个或更多字符!和#(带[^!#] +替代)或感叹号,多次(/ g)。
#2
2
Use "empty string followed by an exclamation mark or empty string preceded by an exclamation mark" in place of your second alternative:
使用“空字符串后跟感叹号或带有感叹号的空字符串”代替您的第二个备选方案:
my @parts = split /#|(?=!)|(?<=!)/, $foo;