Since it is fixed-length scanning, we can use pack() and unpack(): 
my @inp = ("abc_A_bla", "abc_B_bla", "abc_C_bla") ;

print  "@{[ keys %{{ unpack '(x4 A A4)*', pack( '(A*)*', @inp) }}]}";

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In reply to Re: from array to hash with grep by ioannis
in thread from array to hash with grep by jeanluca

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