I do know that for and foreach are synonymous words. I was trying to clarify that in 
for (@array) {$_++}

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$_ is an implicit alias for the current @array element. While in
for (0 .. $#array) {$array[$_]++}

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$_ an alias for the current index.

In your second example there, perl has no idea that $_ is an alias for the "current index." All it knows is that it is an alias for the current list element. The difference between the two examples is only in the contents of the list that the for statement is iterating over.

-sauoq
"My two cents aren't worth a dime.";

In reply to Re^7: grep, map vs. foreach performance by sauoq
in thread grep, map vs. foreach performance by Anonymous Monk

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