you can simply substitute a number into the hash-value s/^>(\d+)/$lista2{$1}/

the following demonstration is safer because it is also catching missing hash entries

use strict;
use warnings;


my %lista2=
  (
   1    =>    "CAT00.3",
   2    =>    "CAT43.1",
   3    =>    "CAT40.3"
  );

while (<DATA>) {
    s/^>(\d+)/$lista2{$1} || die "unknown number $1"/e;
    print 
}


__DATA__
>1
AACTCTGGGACAATGGCACACGGGAAACAGATAATGAACGATCAGCACAGGGAACTAGCG
>2
AACTCTGGGACAATGGCACACGGGAAACAGATAATGAACGATCAGCACAGGGAACTAGCG
>3
AACTCTGGGACAATGGCACACGGGAAACAGATAATGAACGATCAGCACAGGGAACTAGCG
>4

[download]

unknown number 4 at d:/Users/lanx/pm/hash_regex.pl line 14, <DATA> lin
+e 7.
CAT00.3
AACTCTGGGACAATGGCACACGGGAAACAGATAATGAACGATCAGCACAGGGAACTAGCG
CAT43.1
AACTCTGGGACAATGGCACACGGGAAACAGATAATGAACGATCAGCACAGGGAACTAGCG
CAT40.3
AACTCTGGGACAATGGCACACGGGAAACAGATAATGAACGATCAGCACAGGGAACTAGCG

Compilation exited abnormally with code 255 at Sat Apr 28 00:16:17

[download]

Cheers Rolf
(addicted to the Perl Programming Language and ☆☆☆☆ :)
Wikisyntax for the Monastery

update

just noticed, the s/^>(\d+)/$lista2{$1}/ variant will already warn you.

Use of uninitialized value within %lista2 in substitution iterator at hash_regex.pl line 14, <DATA> line 7.

In reply to Re: how to remplace a names in a file by keys with hash by LanX
in thread how to remplace a names in a file by keys with hash by zelman796

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.