Monday, May 24, 2010

What does this PERL expression mean?

/^[-+]?\d+\.\d+$/





Can someone please break this down for me?





Thanks!

What does this PERL expression mean?
that's called a "regular expression"





you may want to do some research on regular expressions to figure out what they mean, but i'll break this down for you:





/^[-+]?\d+\.\d+$/


the first "/" and last "/" are only there to enclose the regular expression:





^[-+]?\d+\.\d+$


the "^" means to check from the beginning and "$" means to check all the way to the end.





[-+]?


the ? means to match 1 or 0 of any of the characters enclosed in the square brackets [ ]...





\d+


this means to match any digit character, represented by \d, and the "+" means to match any digit 1 or more times.





\.


this means to match a period





\d+


same as the other
Reply:everything stays as aamina said except english description: the expression will be true if checked variable represents decimal number (preceding + or - sign is optional)


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