Re: How to write a regular expression to extract a number from an embedded string?

How about this?

  my $string = 'abcdef 5163 1234 5678';
  my $extracted = $string =~ /(5163(?:\d{8}|\s\d{4}\s\d{4}))/;
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Update: modified code. Thanks davido

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Re^2: How to write a regular expression to extract a number from an embedded string? by davido (Cardinal) on Jul 28, 2004 at 20:24 UTC
This solution makes the assumption that if spaces occur, they will always occur at four-digit intervals. The OP didn't say that was the case. While it may be the case, we're not sure. Your use of tr/// is ineffective, at any rate. It's doing nothing. If evaluated in scalar context it would return the number of spaces found, but if you intended to delete spaces, you need to add the /d modifier. However, that would be contrary to what the OP was asking. In his example output, whitespace is preserved. Dave	[reply]

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Re^2: How to write a regular expression to extract a number from an embedded string?
by davido (Cardinal) on Jul 28, 2004 at 20:24 UTC

This solution makes the assumption that if spaces occur, they will always occur at four-digit intervals. The OP didn't say that was the case. While it may be the case, we're not sure.

Your use of tr/// is ineffective, at any rate. It's doing nothing. If evaluated in scalar context it would return the number of spaces found, but if you intended to delete spaces, you need to add the /d modifier. However, that would be contrary to what the OP was asking. In his example output, whitespace is preserved.

Dave

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