ANT element in csv matching

问题:

I need to write a regex to match an element in a comma-separated list, ignoring whitespaces near ,. For example: elem1, elem2 ,elem3, elem4 ,elem5 ,elem6

Any of: elem1 elem2 elem3 elem4 elem5 elem6 should match.

The trailing comma (before end of line) is not allowed.

I tried this pattern:
pattern="(^|/,)\s*@{value}\s*(/,|$)"
but it doesn't work. (False negative)

How can i do that pattern? What's wrong in mine?

Thanks.

回答1:

Interpolation is your problem. And, you can't consume the ',' on both sides, you can only consume it on one side.

Edit - That is if you are searching in a global sense, then you can't consume a comma on both sides. For instance if you want to find ALL of something. If its just find the first match only then a comma on both sides is OK. I don't know about java but, you can't just plop a list into a regex and expect it to match unless its set up as an alternation first. Like "(?:^|,)\\s*(?:elem4|elem6)\\s*(?=,|\$)". For sure you need another escape on the whitespace \\s.

$value = '(elem.)';  
$rx    = "(?:^|,)\\s*$value\\s*(?=,|\$)";

or

$rx    = '(?:^|,)\s*(elem.)\s*(?=,|$)';

In Perl:

use strict;
use warnings;

my $value = '(elem.)';

my $str = ' elem1, elem2 ,elem3, elem4 ,elem5 ,elem6 ';

my $rx = "(?:^|,)\\s*$value\\s*(?=,|\$)";

while ( $str =~ /$rx/g ) {
   print "'$1'\n";
}

Output

'elem1'
'elem2'
'elem3'
'elem4'
'elem5'
'elem6'

回答2:

From your previous question, you want to test, if a csv list contains a special value. This is a different task - and a different ant task too:

<macrodef name="csvcontains">
    <attribute name="value"/>
    <attribute name="list"/>
    <attribute name="casesensitive" default="false"/>
    <sequential>
    <condition property="matched" else="false">
        <contains string="@{list}" substring="@{value}" casesensitive="@{casesensitive}"/>
    </condition>
    </sequential>
</macrodef>

(You may think about renaming the property matched to contained)

回答3:

I found one solution:

The pattern is:

^(.+,\s*|\s*)@{value}(\s*|\s*,.+)$

An usage example is:

<macrodef name="csvcontains">
    <attribute name="value"/>
    <attribute name="list"/>
    <attribute name="propertyName"/>
    <attribute name="casesensitive" default="false"/>
    <sequential>
        <condition property="@{propertyName}" else="false">
            <or>
                <isset property="@{propertyName}"/>
                <matches string="@{list}" pattern="^(.+,\s*|\s*)@{value}(\s*|\s*,.+)$" casesensitive="@{casesensitive}"/>
            </or>
        </condition>
    </sequential>
</macrodef>