Re: Surprised by split

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Re^2: Surprised by split by sk (Curate) on Aug 11, 2005 at 15:42 UTC
Sometimes I have to ask the user to specify the delimiter on the file and they might enter a pipe from the command line. This is how I was handling them - `$opt_d = "\\\|" if ($opt_d eq "\|");` [download] Since i am just splitting the file based on just a string, I guess the `/[$opt_d]/` would do the trick! Thanks Anonymous Monk -SK	[reply] [d/l] [select]
Re^3: Surprised by split by Anonymous Monk on Aug 11, 2005 at 16:19 UTC
That would cause a problem if `$opt_d` equals `^`. Perl seems to handle the cases `/[-]/, /[[]/, /[]]/` as the appropriate single character class, but it trips on `/[^]/`. I wonder whether that's a bug (or a yet unimplemented feature). Of course, you can get all sorts of unexpected nonsense if `$opt_d` is longer than a single character. Or if it's the empty string.	[reply] [d/l] [select]
Re^4: Surprised by split by sk (Curate) on Aug 11, 2005 at 16:59 UTC
Thanks for the info on pitfalls!!! For me, usually it is from a well behaved/nicely formatted data and almost always contains one of the following delimiters `",","\t","\|"," ",":"`	[reply] [d/l]
Re^3: Surprised by split by Anonymous Monk on Aug 11, 2005 at 18:16 UTC
Wouldn't quotemeta avoid this problem, as well as the ones described below?	[reply]
Re^4: Surprised by split by sk (Curate) on Aug 11, 2005 at 19:14 UTC
You are right! That should do it!!! `perl -e ' $str = "hi\|there"; $d = quotemeta("\|"); @a = split /$d/, $st +r; print +($_,$/) for (@a);' __END__ hi there` [download]	[reply] [d/l]
Re^2: Surprised by split by Anonymous Monk on Aug 11, 2005 at 15:40 UTC
Or you can use regular expression quotes when you're giving a regular expression. Using a character class might be helpful if you don't want to learn the language, but I would rather people just learn the language.	[reply]
Re^3: Surprised by split by Anonymous Monk on Aug 11, 2005 at 16:22 UTC
Or you can use regular expression quotes when you're giving a regular expression. What do you mean by that? `qr`? Then you still need to escape the pipe. Using a character class might be helpful if you don't want to learn the language, but I would rather people just learn the language. What on earth do you mean by that?	[reply]
Re^4: Surprised by split by Anonymous Monk on Aug 12, 2005 at 07:21 UTC
What do you mean by that? qr? Then you still need to escape the pipe. That's true. I never indicated anything to the contrary. What on earth do you mean by that? The suggestion to use a character class makes split happy, even when passed a string instead of a proper regular expression. That makes it easier for people who don't know enough about the language they're using to get things working. This is certainly one way to accomplish the goal. Another way would be for those people to actually learn the language, instead of learning ways to hack around their lack of knowledge. I am simply advocating the latter strategy over the former.	[reply]
Re^5: Surprised by split by Anonymous Monk on Aug 12, 2005 at 08:55 UTC
Re^2: Surprised by split by GrandFather (Saint) on Aug 11, 2005 at 20:39 UTC
So you are suggesting that I should use a character class trick to avoid quoting a character that I should know needs to be quoted in a context I should know is a regex and that I should type an extra character to achieve this? I'm lazy and will take the good advice of others who have suggested that `/\\|/` is the way to do it. Perl is Huffman encoded by design.	[reply] [d/l]


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