Re^3: Parsing CSV file

Hello Joma,

I’ll make three observations on the regex code shown:

There’s no point in capturing to $2 if that capture is never used. It would be better to use a non-capturing group here:

while ($line =~ m/"([^"\\]*(?:\\.[^"\\]*)*)",?|([^,]+),?|,/g) {
#                          ^^^
    push(@fields, defined($1) ? $1 : $2);
#                                    ^^
[download]

See perlretut#Non-capturing-groupings.

When testing for definedness, Perl’s // (logical defined-or) operator is useful and elegant:
```
    push @fields, $1 // $2;
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```
See perlop#Logical-Defined-Or.
If you had use warnings at the head of your script (and you should!), you would get a Use of uninitialized value warning each time you try to print an array element whose value is undef. You can fix this easily by substituting an empty string:
```
    push @fields, $1 // $2 // '';
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```

Update: ++choroba for pointing out that the Branch Reset pattern (perlre#Extended-Patterns) is a more elegant option here.

Hope that helps,

Athanasius <°(((>< contra mundum Iustus alius egestas vitae, eros Piratica,

Comment on Re^3: Parsing CSV file Select or Download Code

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Re^4: Parsing CSV file by choroba (Cardinal) on Jul 07, 2016 at 12:26 UTC
Using $1 // $2 smells like you can use the Branch Reset pattern (5.10+), which restarts the capture group numbering on each `\|` : `while ($line =~ m/(?\|"([^"\\](?:\\.[^"\\]))",?\|([^,]+),?\|,)/g) { print $1 // q(), "\n"; }` [download] ($q=q:Sq=~/;[c](.)(.)/;chr(-\|\|-\|5+lengthSq)`"S\|oS2"`map{chr \|+ord }map{substrSq`S_+\|`\|}3E\|-\|`7*2-3:)=~y+S\|`+$1,++print+eval$q,q,a, [download]	[reply] [d/l] [select]