(PHP 4, PHP 5, PHP 7)
strtr — ת��ָ���ַ�
$str
, string $from
, string $to
) : string$str
, array $replace_pairs
) : string
�ú������� str ��һ�������������� from ��ָ�����ַ�ת��Ϊ to ����Ӧ���ַ���
���磬 $from[$n]��ÿ�εij��ֶ��ᱻ�滻Ϊ
$to[$n]������ $n ��������������Ч��λ��(offset)��
��� from �� to ���Ȳ���ȣ���ô������ַ����ֽ������ԡ� str �ij��Ƚ���ͷ��ص�ֵһ����
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 The return value is a string where all the occurrences of the array keys have been replaced by the corresponding values.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.
str��ת�����ַ�����
from
�ַ������뽫Ҫ��ת����Ŀ���ַ� to ���Ӧ��Դ�ַ���
to
�ַ������뽫Ҫ��ת�����ַ� from ���Ӧ��Ŀ���ַ���
replace_pairs
���� replace_pairs ��������ȡ�� to �� from ��������Ϊ������ array('from' => 'to', ...) ��ʽ���ֵ����顣
����ת������ַ�����
��� replace_pairs �а���һ�����ַ�����""��������ô������ FALSE��
If the str is not a scalar
then it is not typecasted into a string, instead a warning is raised and
NULL is returned.
Example #1 strtr() ����
<?php
$addr = strtr($addr, "???", "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.
Example #2 ʹ������������ strtr() ����
<?php
$trans = array("hello" => "hi", "hi" => "hello");
echo strtr("hi all, I said hello", $trans);
?>
�������̻������
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.
Example #3 strtr() behavior comparison
<?php
echo strtr("baab", "ab", "01"),"\n";
$trans = array("ab" => "01");
echo strtr("baab", $trans);
?>
�������̻������
1001 ba01