To get the index of elements in fields containing /, I use the following but get an error msg:
@ind = grep($fields[$_] =~ /\/\/]);
Search pattern not terminated
2 Answers
For the sake of completeness, here's how it should look like (if array in question is @fields variable):
my @slash_indexes = grep { $fields[$_] =~ m~/~ } 0..$#fields;
Demo. The code given in the question misses the second param of grep - the list that should be grepped. Considering you need to collect indexes, you need to pass indexes of the original array into grep as well, and not the array itself.
6 Comments
carol
Doesn't work with any of them Not enough arguments for grep at file.pl line 19, near "/\//)" Execution of file.pl aborted due to compilation errors. Not enough arguments for grep at file.pl line 19, near "m#/#)" Execution of file.pl aborted due to compilation errors.
raina77ow
@carol Have you checked the demo, how it's different from your code? Or have you somehow commented on another answer within this one's thread - without actually checking it? )
carol
this one seems to work but as it was posted even with removing \, didn't @ind = grep{$fields[$_] =~ /\//} 0..$#fields;
carol
how can I exclude the 0/0 expressions in the same line,i.e taking all expressions containing / except 0/0 @ind = grep{$fields[$_] =~ /\//} 0..$#fields; and test in another line if (grep($colNames[$curr_ind] !~ /0\/0/)){ print "$colNames[$curr_ind]\t"; } which doesn't work
raina77ow
You can combine two expressions in the same block:
grep { $fields[$_] =~ m~/~ && $fields[$_] ne '0/0' }. |
You are escaping the / that should terminate your regular expression.
Just remove the last \ from before it.
1 Comment
raina77ow
That's why it's often advantageous to choose another delimiter:
=~ m#/# is more readable than =~ /\//.
grepshould have two parameters, not one: what list are you grepping?