Re^2: REGEX Match Single Digit

kennethk -

*SLAPS forehead*
That simple, eh? That will match just the number 1, and not 11, or 111, etc. Lemme try it out. Does that work if I read the number one from <STDIN> and chomp the newline? Is the digit 1 now string 1?

Comment on Re^2: REGEX Match Single Digit

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Re^3: REGEX Match Single Digit by ikegami (Patriarch) on Aug 28, 2009 at 16:11 UTC
That will match just the number 1, and not 11, or 111, etc. It matches "1" and "1\n" only. `/^1$/`: At the start of the input, match "1", then optionally match "\n", then match the end of the input string. `/^1\z/` will only match "1".	[reply] [d/l] [select]
Re^3: REGEX Match Single Digit by kennethk (Abbot) on Aug 28, 2009 at 16:21 UTC
One of the things I love about Perl is the weak typing on scalars. The digit 1 and the string "1" have roughly equivalent internal representations and which one is used depends upon the context of your call. For example the line `print "1 line of text" + 1;` will output the string "2". You start with a string and a number combined with the + operator. That operator takes two numbers as arguments, so perl attempts to convert the string to a number - this truncates from the first non-numeric character. We then evaluate 1+1 = 2. That two is then passed to the print subroutine, which takes a string input. Therefore, 2 is converted to "2" and output to STDOUT. Coming from a strongly-typed background, that still fills me with a profound warmth every time I do it.	[reply] [d/l]