$str
, array $replace_pairs
) If given three arguments, this function returns a copy of str
where all occurrences of each (single-byte) character in from
have been translated to the corresponding character in to
, i.e., every occurrence of $from[$n] has been replaced with $to[$n], where $n is a valid offset in both arguments.
If from
and to
have different lengths, the extra characters in the longer of the two are ignored. The length of str
will be the same as the return value's.
If given two arguments, the second should be an array in the form array('from' => 'to', ...). The return value is a string where all the occurrences of the array keys have been replaced by the corresponding values. The longest keys will be tried first. Once a substring has been replaced, its new value will not be searched again.
In this case, the keys and the values may have any length, provided that there is no empty key; additionally, the length of the return value may differ from that of str
. However, this function will be the most efficient when all the keys have the same size.
The string being translated.
The string being translated to to
.
The string replacing from
.
The replace_pairs
parameter may be used instead of to
and from
, in which case it's an array in the form array('from' => 'to', ...).
Returns the translated string.
If replace_pairs
contains a key which is an empty string (""), FALSE
will be returned. If the str
is not a scalar then it is not typecasted into a string, instead a warning is raised and NULL
is returned.
<?php //In this form, strtr() does byte-by-byte translation //Therefore, we are assuming a single-byte encoding here: $addr = strtr($addr, "äåö", "aao"); ?>
The next example shows the behavior of strtr() when called with only two arguments. Note the preference of the replacements ("h" is not picked because there are longer matches) and how replaced text was not searched again.
<?php $trans = array("h" => "-", "hello" => "hi", "hi" => "hello"); echo strtr("hi all, I said hello", $trans); ?>
The above example will output:
hello all, I said hi
The two modes of behavior are substantially different. With three arguments, strtr() will replace bytes; with two, it may replace longer substrings.
<?php echo strtr("baab", "ab", "01"),"\n"; $trans = array("ab" => "01"); echo strtr("baab", $trans); ?>
The above example will output:
1001 ba01
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