Multiple condition IF statement using grep and eq

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

I have a IF statement in this form:

if (grep $_ == $F[1],73,89,121,101,117,69,77,67,115,81,97,65,113) {

That compares values held within $F1 to those listed. I wish to add an additional condition that checks another variable other than $F1 but i'm struggling somewhat with the syntax and how this will work with the grep. For example:

if (grep $_ == $F[1],73,89,121,101,117,69,77,67,115,81,97,65,113 && $inext eq "Global.SAM")

Each condition works individually, but the latter condition testing $inext is ignored when written in this form. Why is this happening and what could be a solution to the problem?

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Re: Multiple condition IF statement using grep and eq by toolic (Bishop) on May 04, 2016 at 17:05 UTC
Use parentheses to group your terms. Tip #6 from the Basic debugging checklist: B::Deparse `perl -MO=Deparse,p if (grep(($_ == $F[1]), 73, 89, 121, 101, 117, 69, 77, 67, 115, 81, 97 +, 65, $inext eq 'Global.SAM')) {` [download] Change your code to: `if ( (grep $_ == $F[1],73,89,121,101,117,69,77,67,115,81,97,65,113) && + ($inext eq "Global.SAM") ) {` [download]	[reply] [d/l] [select]
Re^2: Multiple condition IF statement using grep and eq by Anonymous Monk on May 04, 2016 at 17:11 UTC
Thank you! I knew it would be something simple. That tip is going to be super useful too.	[reply]
Re^3: Multiple condition IF statement using grep and eq by Marshall (Canon) on May 04, 2016 at 17:23 UTC
As further suggestion, move the "cheap test" to the front. Grep implies a foreach loop and is much more "expensive" than a simple equality test. The "if" statement is executed from left to right - don't bother with the grep if the first test fails. Also consider the block form of grep: `if ($inext eq "Global.SAM" and grep{$_ == $F[1]} 73,89,121,101,117,69,77,67,115,81,97,65,113) {}` [download] "and" is a lower priority operator than "&&" so no extra parens required.	[reply] [d/l]