in reply to adding a column of integers

perl -lne "$sum+=$_}{print $sum"

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Re^2: adding a column of integers
by Eimi Metamorphoumai (Deacon) on Sep 02, 2004 at 14:19 UTC
    Or more verbose, but more understandable (without delving into the actual expansion of -n) 
    perl -lne '$sum+=$_; END{print $sum}'

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    The END block is executed after everything else. You can also use a corresponding BEGIN block before anything else runs, and there are others (CHECK and INIT, having to do with compile time) for fancy stuff.
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Re^2: adding a column of integers
by Smylers (Pilgrim) on Sep 02, 2004 at 16:10 UTC

    If you're in the mood for doing sneaky tricks with -n then why not be really sneaky:

    perl -lne '$;+=$_}{print$'

    Smylers

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        That's overkill; miss out 3 of the characters and it still works:

        perl -lpe '$-+=$_}{$_=$-'

        Smylers

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Re^2: adding a column of integers
by Random_Walk (Prior) on Sep 02, 2004 at 15:51 UTC

    update - whoops

    I just saw his tail -1 at the end, he is looking for a final total not a running one, DOH!. So option 2 below works just fine

    Original dumb post

    This does not work for me, is this my old perl (5.005_03) or am I doing something wrong ? If I add a continue it will work. Here is some output, I have added the > before the numbers I entered just for clarity. 
    :perl -lne "$sum+=$_}{print $sum"
syntax error at -e line 1, near "+="
Execution of -e aborted due to compilation errors.
:perl -lne '$sum+=$_}{print $sum'
>1
>2
>3
:perl -lne '$sum+=$_}continue{print $sum'
>1
1
>2
3
>3
6
>4
10

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    Cheers,
    R.
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