---
name: tr
status: documented
runtime: pp
source: src/runtime/pp/regex/trans.rs
---
```{index} single: tr; Perl built-in (pp runtime)
```

# tr

///

## Synopsis

```perl
$str =~ tr/searchlist/replacementlist/;
$str =~ y/a-z/A-Z/;          # y is a synonym
my $count = ($s =~ tr/a//);   # count occurrences
my $new   = $s =~ tr/a-z/A-Z/r;  # /r returns copy
```

## Description

Performs character-by-character transliteration on a string.

Transliterates characters in the target string according to a
precompiled translation table.  Each character found in the search
list is replaced by the corresponding character in the replacement
list.

The target string is obtained from the targ pad slot, the stack,
or `$_`.  For `tr///` (OP_TRANS), the string is modified in place
and the count of translated characters is pushed.  For `tr///r`
(OP_TRANSR), a new modified copy is pushed instead.

Modifiers (encoded in op_private):
- `/c` (0x20): Complement the search list
- `/d` (0x80): Delete found but unreplaced characters
- `/s` (0x08): Squash duplicate replaced characters

## See also

s///, m//, perlop