Perl Map

map EXPR,LIST

Evaluates the BLOCK or EXPR for each element of LIST (locally setting $_ to each element) and returns the list value composed of the results of each such evaluation. In scalar context, returns the total number of elements so generated. Evaluates BLOCK or EXPR in list context, so each element of LIST may produce zero, one, or more elements in the returned value.

Example 1: Finding square of the numbers

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    my @arr = (1..5);
    say "@arr \n";
    Prints: 1 2 3 4 5

    my @unique = map { $_ * $_ } @arr;
    say "@unique \n";
    Prints: 1 4 9 16 25 

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Example 2: Square even, cube odd numbers. Use Perl modulus operator to distinguish odd and even numbers.

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    my @arr = (1..5);
    say "@arr";
    Prints: 1 2 3 4 5

    my @unique = map { $_%2 ? $_*$_*$_ : $_*$_ } @arr;
    say "@unique";
    Prints: 1 4 27 16 125 

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Example 3: Square even, cube odd numbers. Use Perl and operator to distinguish odd and even numbers.

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    my @arr = (1..5);
    say "@arr";
    Prints: 1 2 3 4 5

    my @unique = map { $_&1 ? $_*$_*$_ : $_*$_ } @arr;
    say "@unique";
    Prints: 1 4 27 16 125 

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Example 4: Convert to uppercase

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    my @lover = qw("aa bbb ccc ddddd eeee fff");
    say "@lover";
    Prints: "aa bbb ccc ddddd eeee fff"

    my @upper = map { uc } @lover;
    say "@upper";
    Prints: "AA BBB CCC DDDDD EEEE FFF" 

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