Re: a q-n-d csv_join function

Elegant. Some minor points:

need to consider other types of whitespace, so [ ,] => [\s,]
passing a reference to an array is more efficient than passing the array - if you pass the array you will have to pass by reference each array member rather than just the single array reference. To preserve the calling syntax of csv_join(@someArray) use the prototype \@.
However, you can only use \@ if your parameters are arrays. If hardcoded lists are used as parameters, e.g. csv_join('a','b','c') instead of arrays, e.g. csv_join(@aFields), then you will need to use the version that passes the entire array. The \@ prototype would complain about extra parameters and failed attempts to take references of constant items.
interpolating quotes unnecessary for ","
~~my @x is unnecessary - map copies on its own~~
golf score (which shouldn't matter, but if you care) - use /.../ not m{...} and s{...}{...}

With revisions (using the \@ protoype)p>

sub csv_join(\@) {
 join ',', map {s/"/""/g || /[\s,]/ ? qq{"$_"} : $_} (my @x=@{$_[0]});
}
[download]

With revisions (passing the entire array):

sub csv_join {
  join ',', map { s/"/""/g || /[\s,]/ ? qq{"$_"} : $_} (my @x=@_);
}
[download]

Best, beth

Update: Re-added my @x. Thanks, jwkrahn. I had overlooked the effect of s/// on the elements of @_.

Update 2: Added an alternative if the function needs to be called with hard coded lists, e.g. csv_join('a','b','c')

Comment on Re: a q-n-d csv_join function Select or Download Code

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Re^2: a q-n-d csv_join function by jwkrahn (Abbot) on Mar 02, 2009 at 01:44 UTC
my @x is unnecessary - map copies on its own map in the example modifies `$_` and `@_` is an alias to the original array so you need the copy in order not to modify the original array passed to the subroutine.	[reply] [d/l] [select]
Re^2: a q-n-d csv_join function by perl5ever (Pilgrim) on Mar 02, 2009 at 01:42 UTC
Re: `my @x`... if you do not pass the arguments as an array-ref, then something like `my @x` is necessary. Without the `my @x =`, perl will complain with: `Modification of a read-only value attempted at ...`. unless these is another way around this problem...	[reply] [d/l] [select]
Re^3: a q-n-d csv_join function by ELISHEVA (Prior) on Mar 02, 2009 at 02:39 UTC
Hmmm... my test code (without `my @x`) didn't trigger that warning, but then I was passing arrays and not hard-coded lists of data. I think you would get that problem if you were calling `csv_join('a', 'b', 'c')` for example. Hard coded lists would also be a problem with the `\@` prototype since it needs to take a reference to the array that was passed to `csv_join('a','b','c')` and hard coded lists don't have references. In fact, you would get something like this if the prototype is `\@` and you called `csv_join('a', 'b', 'c')` `Type of arg 1 to main::csv_join must be array (not constant item) at M +onks/QuickCsvJoin.pm line 33, near "'c') " Too many arguments for main::csv_join at Monks/QuickCsvJoin.pm line 33 +, near "'c') "` [download] If you need to make calls like `csv_join('a','b','c')` rather than `csv_join(@aFields)`, then you will have to pass the array rather than just a reference to it. I've updated the original reply with the alternative. See above. Best, beth	[reply] [d/l] [select]
Re^2: a q-n-d csv_join function by GrandFather (Saint) on Mar 02, 2009 at 02:26 UTC
Update: Re-added my @x. Thanks, jwkrahn. I had overlooked the effect of s/// on the elements of @_. which just goes to amplify my earlier comment concerning 'correctness and maintainability' ;-). True laziness is hard work	[reply]