在字符串php中交换两个单词 [英] swap two words in a string php

问题描述

假设有一个字符串"foo boo foo boo"，我想用boo替换所有foo，用foo替换booes.预期输出为"boo foo boo foo".我得到的是"foo foo foo foo foo".如何获得预期的输出而不是当前的输出?

Suppose there's a string "foo boo foo boo" I want to replace all fooes with boo and booes with foo. Expected output is "boo foo boo foo". What I get is "foo foo foo foo". How to get expected output rather than current one?

    $a = "foo boo foo boo";
    echo "$a\n";
    $b = str_replace(array("foo", "boo"), array("boo", "foo"), $a);
    echo "$b\n";
    //expected: "boo foo boo foo"
   //outputs "foo foo foo foo"

推荐答案

使用 strtr

从手册中:

如果给定两个参数，则第二个参数应为array('from'=>'to'，...)形式的数组.返回值是一个字符串，其中所有出现的数组键都已被相应的值替换.最长的键将首先尝试.替换子字符串后，将不再搜索其新值.

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 The return value is a string where all the occurrences of the array keys have been replaced by the corresponding values.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.

在这种情况下，如果没有空键，则键和值可以具有任意长度.另外，返回值的长度可能与str的长度不同.但是，当所有键的大小相同时，此功能将是最有效的.

In this case, the keys and the values may have any length, provided that there is no empty key; additionaly, 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.

$a = "foo boo foo boo";
echo "$a\n";
$b = strtr($a, array("foo"=>"boo", "boo"=>"foo"));
echo "$b\n"; 

输出

foo boo foo boo
boo foo boo foo

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