我想在特定模式之后插入一个项目。在我的情况下，我想插入x后，每秒钟a在一个数组。在第6个a之后，我的代码不能正常工作:
$array = array("a","a","a","a","a","a","b","a","a");
$out = array();
foreach ($array as $key=>$value){
$out[] = $value; // add current letter to new array
if($value=='a' && $array[$key-1]=='a' && $out[$key] !='x'){ // check if current and last letter are a
$out[] = 'x'; // if so add an x to the array
}
}
print_r($out);
正确答案在最后
这就是你要找的吗?
<?php
$array = array("a","a","a","a","a","a","b","a","a");
foreach ($array as $key => $value){
if ($key == 0 || $key == 1) {
$array[$key] = $value;
} elseif($array[$key-1] == 'a' && $array[$key-2] == 'a' && $array[$key] == 'a') {
$array[$key] = 'x';
} else {
$array[$key] = $value;
}
}
$count = count($array);
if ($array[$count-1] == 'a' && $array[$count-2] == 'a') {
$array[] = 'x';
}
print_r($array);
?>
如果我理解正确，在2 a之后，你想把x放入新的数组。
请现在核对。如果数组中最后两个是a，则会添加一个新元素x。
有例外，但仍然工作:
<?php
$array = array("a","a","a","a","a","a","b","a","a");
foreach ($array as $key => $value){
if($array[$key-1] == 'a' && $array[$key-2] == 'a' && $array[$key] == 'a') {
$array[$key] = 'x';
}
}
$count = count($array);
if ($array[$count-1] == 'a' && $array[$count-2] == 'a') {
$array[] = 'x';
}
print_r($array);
?>
更新-正确代码
我认为下面的代码可以满足你所有的需求:
<?php
$arr = array("a","w","a","d","a","a","b","a","a", "w");
$arr_count = count($arr);
for ($i = 0; $i < $arr_count; $i++){
if (!empty($arr[$i+1]) && $arr[$i] == $arr[$i+1]) {
$first_half = array_slice($arr, 0, $i+2);
$second_half = array_slice($arr, $i+2, $arr_count);
if (count($second_half) > 0) {
$arr = array_merge($first_half, ["x"], $second_half);
}
}
}
$count = count($arr);
if ($arr[$count-1] == 'a' && $arr[$count-2] == 'a') {
$arr[] = 'x';
}
print_r($arr);
?>
正如评论中提到的，在这种特殊情况下，您当然可以使用正则表达式:
$pattern = '/a{2}/';
$replacement = '$0x';
$out = str_split(preg_replace(
$pattern,
$replacement,
implode('', $array)
));
基本上，我们将字符粘合在一起(使用implode)形成字符串，然后用"aax"替换每个"aa"。之后使用str_split将string拆分回数组。