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How to catch the last number in a string in Perl?

Posted on 2013-06-28
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How can I catch the "27" in the following string in Perl?


The McCabe complexity of 'myFile' is 27.

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The general question is like, how to catch XX in the following string

The McCabe complexity of 'filename' is XX.

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Question by:Tolgar
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by:nemws1
Comment Utility
Well, since they're the only numbers in that line, just look for digits:

$line = "The McCabe complexity of 'myFile' is 27.";
$line =~ m/.*?(\d+).*/;
$number = $1;
print $number, "\n";

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by:nemws1
Comment Utility
Are there going to be any numbers *before* the "27" in this line?
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Author Comment

by:Tolgar
Comment Utility
The filename may include numbers. Or the worst case scenario is the file name can be only numbers. But I guarantee that the file name will be in single quotes.
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Expert Comment

by:ozo
Comment Utility
$line = "The McCabe complexity of 'myFile2' is 27.";
$number =  (split/\D+/,$line)[-1];
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Author Comment

by:Tolgar
Comment Utility
And the other thing is, I read a file into a string. So When we search for the number we should also check that it has this patttern:

The McCabe complexity of 'someTextInHere' someNumberInHere

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So the string will be some thing like this:

some characters in here and some other characters
in here then we also have stuff in here then we have The McCabe complexity of 'myFile' 43
and we also have characters in the file.

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How are going to catch 43 in this long string?

I guarantee that we will have "The McCabe complexity of 'SOMEFileNAME' " before the number.
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Accepted Solution

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nemws1 earned 167 total points
Comment Utility
Try this, going back to my first suggestion (ozo's is better if you indeed just want the last number from a line of text:)

$line = "there may be some other stuff here The McCabe complexity of 'myFile' is 27.";
$line =~ m/.*?The McCabe complexity of '.*?' is (\d+).*/;
$number = $1;
print $number, "\n";

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Assisted Solution

by:ozo
ozo earned 166 total points
Comment Utility
($number) = "The McCabe complexity of 'myFile' 43" =~ /The McCabe complexity of '.*' (?:is )?(\d+)/;
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Assisted Solution

by:wilcoxon
wilcoxon earned 167 total points
Comment Utility
I'd do a slight modification of nemws1 and ozo's answer.  With both of theirs, it will be incorrect if there is a single quote followed by a number later in the same line (however, mine won't work if there can be single quotes in the filename itself).
$line = "there may be some other stuff here The McCabe complexity of 'myFile' is 27.";
($number) = $line =~ m{The McCabe complexity of '[^']*'(?: is)? (\d+)};

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Is it accurate that the is may not always be present?  You don't say so explicitly (unless I missed it) but your example of the long string does not have the "is".  If it is not optional then you can change "(?: is)?" into just plain " is".
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