php php使用foreach将值插入数组中
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php insert value into array of arrays using foreach
提问by Benjamin Thvedt
I have a pretty basic question but I am stuck. I am pretty new to php and I have an array like this:
我有一个非常基本的问题，但我被卡住了。我对 php 很陌生，我有一个这样的数组：
$array = array(
'one' => 1,
'two' => array('key1' => 'val1','key2' => 'val2'),
'three' => array('key1' => 'val1','key2' => 'val2'),
'four' => array('key1' => 'val1','key2' => 'val2')
);
and for each of the arrays in the array (that is, 'two, 'three', and 'four'), I want to insert 'key3' => 'val3' into those arrays.
对于数组中的每个数组（即“二”、“三”和“四”），我想将“key3”=>“val3”插入到这些数组中。
I tried this:
我试过这个：
foreach($array as $item) {
if (gettype($item) == "array") {
$item['key3'] = 'val3';
}
}
But it doesn't work, and I'm not sure why. Using various print_r's all over the place, it seems to insert 'key3' => 'val3' into $item if I print it out in the loop, but the original array seems unchanged. I also tried a regular for loop but that didn't work either.
但它不起作用，我不知道为什么。到处使用各种print_r，如果我在循环中将其打印出来，它似乎将'key3' => 'val3' 插入到$item 中，但原始数组似乎没有变化。我也尝试了一个常规的 for 循环，但这也不起作用。
回答by kapa
foreachworks with a copy of $item, so you cannot modify your original array inside the foreach. One way to work around this is to use the &operator.
foreach与 的副本一起使用$item，因此您无法修改foreach. 解决此问题的一种方法是使用&运算符。
foreach($array as &$item) {
if (is_array($item)) {
$item['key3'] = 'val3';
}
}
Another, more elegant way would be to use array_walk():
另一种更优雅的方法是使用array_walk()：
array_walk($array, function (&$v, $k) {
if (is_array($v)) {
$v['key3'] = 'val3';
}
});
This example will work from PHP 5.3, where Closures were introduced.
这个例子适用于 PHP 5.3，其中引入了闭包。
回答by hek2mgl
PHP has a function to check whether a variable is an array or not: is_array(). Use this:
PHP 有一个函数来检查一个变量是否是一个数组：is_array(). 用这个：
if (is_array($item)) { ...
回答by Asad
while looping with foreach use key like :
使用 foreach 循环时使用键，例如：
foreach($array as $key => $item){
$array[$key]['newElement'] = "newValue";
}
