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Re: Conditional array initialisation?

by Kordaff (Sexton)
on Jul 12, 2013 at 19:22 UTC ( #1044055=note: print w/ replies, xml ) Need Help??


in reply to Conditional array initialisation?

From perldoc perlop: Logical Defined-Or Although it has no direct equivalent in C, Perl's // operator is related to its C-style or. In fact, it's exactly the same as ||, except that it tests the left hand side's definedness instead of its truth. Thus, EXPR1 // EXPR2 returns the value of EXPR1 if it's defined, otherwise, the value of EXPR2 is returned. (EXPR1 is evaluated in scalar context, EXPR2 in the context of // itself). Usually, this is the same result as defined(EXPR1) ? EXPR1 : EXPR2 (except that the ternary-operator form can be used as a lvalue, while EXPR1 // EXPR2 cannot). This is very useful for providing default values for variables. If you actually want to test if at least one of $a and $b is defined, use defined($a // $b) .


Comment on Re: Conditional array initialisation?
Re^2: Conditional array initialisation?
by BrowserUk (Pope) on Jul 12, 2013 at 19:24 UTC

    I'm not sure how you think any of that is relevant.


    With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority".
    In the absence of evidence, opinion is indistinguishable from prejudice.

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