php array_map最初将第一个键更改为零 [英] php array_map changes the first key to zero when it was originally one
问题描述
我有一个数组,其中第一个键以一个开头,并且我需要这样。
I have an array whick first key starts with one, and I need it like that.
//first iteration of $collections
$collections[1] = $data1;
$collections[2] = $data2;
...
//It does not have to start with zero for my own purposes
所以我做了这样的事情:
So I do the stuff needed like this:
//count($collections) = 56;
$collections = array_map(function($array)use($other_vars){
//more stuff here
//finally return:
return $arr + ['newVariable'=$newVal];
},$collections);
当 var_dump($ collections);
时
但是,当我想向数组中添加另一个变量时,如下所示:
However, when I want to add another variable to the array like these:
//another array starting at one //count($anotherArray) = 56;
$anotherArray[] = ['more'=>'values'];
$collections = array_map(function($arr,$another)use($other_vars){
//more stuff here
//finally return:
return $arr + ['newVariable'=$newVal,'AnotherVar'=>$another['key']];
},$collections,$anotherArray);
然后,如果我再次迭代$ collections,它现在从零开始。为什么?如何在第一个键中使其从1开始而不是0?
有什么想法吗?
Then if I iterate $collections again, it now starts at zero. Why? How can I make it start from 1 instead of zero in the first key? Any ideas?
那为什么第一个键变成零呢?我如何保持它为一体?
So why is the first key changed to zero? How can I keep it to be one?
您可以通过执行以下代码来重现该问题(例如在php在线上):
You can reproduce the problem by executing the following code (for example on php online):
$collections[1]=['data1'=>'value1'];
$collections[2]=['data2'=>'value2'];
$collections[3]=['data3'=>'value3'];
$collections[4]=['data4'=>'value4'];
$another[1]=['AnotherData'=>'AnotherVal1'];
$another[2]=['AnotherData'=>'AnotherVal2'];
$another[3]=['AnotherData'=>'AnotherVal3'];
$another[4]=['AnotherData'=>'AnotherVal4'];
var_dump($collections);
echo '<hr>';
var_dump($another);
echo '<hr>';
$grandcollection=array_map(function($a){
return $a + ['More'=>'datavalues'];
},$collections);
var_dump($grandcollection);
echo '<hr>';
$grandcollection2 = array_map(function($a,$b){
return $a + ['More'=>'datavalues','yetMore'=>$b['AnotherData']];
},$collections,$another);
var_dump($grandcollection2);
现在添加鲁路修
Now adding the solution suggested by lerouche
echo '<hr>';
array_unshift($grandcollection2, null);
unset($grandcollection2[0]);
var_dump($grandcollection2);
现在可以按预期运行
推荐答案
在创建 $ collections
之后,用无用值取消移动数组,然后将其删除:
After your $collections
has been created, unshift the array with a garbage value and then delete it:
array_unshift($collections, null);
unset($collections[0]);
这会将所有内容向下移动一个,将第一个实数元素移至索引1。
This will shift everything down by one, moving the first real element to index 1.
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