Using map is a lot of overhead for just assigning to a hash. 
use Benchmark;
timethese(1000, {
    'map1' => sub {
        my %str = map {($_,1)} (0..1024);
    },
    'arry' => sub {
        my %str = ();
        @str{0..1024} = (1)x1025;
    }
});

Benchmark: timing 1000 iterations of arry, map1...
      arry:  1 wallclock secs ( 1.36 usr +  0.00 sys =  1.36 CPU) @ 73
+5.29/s (n=1000)
      map1:  3 wallclock secs ( 3.11 usr +  0.00 sys =  3.11 CPU) @ 32
+1.54/s (n=1000)

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In reply to Re^3: Unhappy returns by Keystroke
in thread Unhappy returns by tlm

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