Basic but stupid problem i cannot wrap my head around

baxy77bax has asked for the wisdom of the Perl Monks concerning the following question:

hi,

so the problem is the folloving:

perl -le '$t="a/b"; if ($t =~/^(.*?)\//){$z=$1}elsif($t=~/\/(.*)/){$z=
+ $1} print $z'
#prints a

perl -le '$t="/b"; if ($t =~/^(.*?)\//){$z=$1}elsif($t=~/\/(.*)/){$z= 
+$1} print $z'
#prints nothing
[download]

it is probably something stupid , as i am quite tired but why isn't the second case being evaluated (or it is but why is it returning 0 )

thnx

baxy

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Re: Basic but stupid problem i cannot wrap my head around by Corion (Patriarch) on Aug 06, 2020 at 09:06 UTC
In your first input string, there is an `a`, this gets matched and then assigned to `$z` (and printed). In your second input string, there is an empty string before the `/`, and no `a`. This gets matched and then assigned to `$z` (and printed). Maybe you don't want the stuff in front of the slash to be empty? `perl -le '$t="/b"; if ($t =~/^(+?)\//){$z=$1}elsif($t=~/\/(.)/){$z=$ +1} print $z'` [download]	[reply] [d/l] [select]
Re: Basic but stupid problem i cannot wrap my head around by jeffenstein (Hermit) on Aug 06, 2020 at 16:50 UTC
Are you expecting "b" for the second example? `/^(.*?)\//` matches both strings, but $1 in the second example is the zero-length string before the slash. Maybe you meant `/^(.+?)\//`?	[reply] [d/l] [select]
Re: Basic but stupid problem i cannot wrap my head around (oneliners) by Anonymous Monk on Aug 06, 2020 at 10:17 UTC
Its the oneliners that stun. Shake it off. Make a file.	[reply]
Re: Basic but stupid problem i cannot wrap my head around by perlfan (Parson) on Aug 11, 2020 at 01:33 UTC
I find it hard to believe this is the general case of what you're attempting. But if it is, both cases will be covered if you just split on `/` and print the first element.	[reply] [d/l]