FAQ 4.31 How can I split a [character] delimited string except when inside [character]?
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From: PerlFAQ Server on 22 Jun 2010 06:00 This is an excerpt from the latest version perlfaq4.pod, which comes with the standard Perl distribution. These postings aim to reduce the number of repeated questions as well as allow the community to review and update the answers. The latest version of the complete perlfaq is at http://faq.perl.org . -------------------------------------------------------------------- 4.31: How can I split a [character] delimited string except when inside [character]? Several modules can handle this sort of parsing--"Text::Balanced", "Text::CSV", "Text::CSV_XS", and "Text::ParseWords", among others. Take the example case of trying to split a string that is comma-separated into its different fields. You can't use "split(/,/)" because you shouldn't split if the comma is inside quotes. For example, take a data line like this: SAR001,"","Cimetrix, Inc","Bob Smith","CAM",N,8,1,0,7,"Error, Core Dumped" Due to the restriction of the quotes, this is a fairly complex problem. Thankfully, we have Jeffrey Friedl, author of *Mastering Regular Expressions*, to handle these for us. He suggests (assuming your string is contained in $text): @new = (); push(@new, $+) while $text =~ m{ "([^\"\\]*(?:\\.[^\"\\]*)*)",? # groups the phrase inside the quotes | ([^,]+),? | , }gx; push(@new, undef) if substr($text,-1,1) eq ','; If you want to represent quotation marks inside a quotation-mark-delimited field, escape them with backslashes (eg, "like \"this\"". Alternatively, the "Text::ParseWords" module (part of the standard Perl distribution) lets you say: use Text::ParseWords; @new = quotewords(",", 0, $text); -------------------------------------------------------------------- The perlfaq-workers, a group of volunteers, maintain the perlfaq. They are not necessarily experts in every domain where Perl might show up, so please include as much information as possible and relevant in any corrections. The perlfaq-workers also don't have access to every operating system or platform, so please include relevant details for corrections to examples that do not work on particular platforms. Working code is greatly appreciated. If you'd like to help maintain the perlfaq, see the details in perlfaq.pod. |