php 如何将空值转换为php数组中的空字符串？
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How to convert the null values to empty string in php array?
提问by XMen
I want to convert this array that Array[4] should not give null it can give blank space (empty string).
我想转换这个数组， Array[4] 不应该给 null 它可以给空格（空字符串）。
Array (
[0] => 1
[1] => 4
[2] => 0
[3] => V
[4] =>
[5] => N
);
(The reason for the change, unrelated to the general question)
（更改原因，与一般问题无关）
Fatal error: Uncaught exception
'PDOException' with message 'Database
error [23000]: Column 'message' cannot
be null, driver error code is 1048' in
回答by MythThrazz
PHP 5.3+
PHP 5.3+
$array = array_map(function($v){
return (is_null($v)) ? "" : $v;
},$array);
回答by Kel
Then you should just loop through array elements, check each value for null and replace it with empty string. Something like that:
然后你应该循环遍历数组元素，检查每个值是否为空并将其替换为空字符串。类似的东西：
foreach ($array as $key => $value) {
if (is_null($value)) {
$array[$key] = "";
}
}
Also, you can implement checking function and use array_map()function.
此外，您可以实现检查功能并使用array_map()功能。
回答by hexiecode
This will map the array to a new array that utilizes the null ternary operator to either include an original value of the array, or an empty string if that value is null.
这会将数组映射到一个新数组，该数组使用空三元运算符来包含数组的原始值，或者如果该值为空则包含一个空字符串。
$array = array_map(function($v){
return $v ?: '';
},$array);
回答by Anton Kolenkov
There is even better/shorter/simpler solution. Compilation of already given answers. For initial data
还有更好/更短/更简单的解决方案。已经给出答案的汇编。对于初始数据
[1, 4, "0", "V", null, false, true, 'true', "N"]
[1, 4, "0", "V", null, false, true, 'true', "N"]
with
和
$result = array_map('strval', $arr);
$resultwill be
$result将是
['1', '4', '0', 'V', '', '', '1', 'true', 'N']
['1', '4', '0', 'V', '', '', '1', 'true', 'N']
This should work even in php4 :)
即使在 php4 中，这也应该可以工作 :)
回答by rrCKrr
You can use this instead.
您可以改用它。
array_map(function($val){return is_null($val)? "" : $val;},$result);
回答by TrophyGeek
Here's a technique I haven't seen mentioned in the above answers:
这是我在上述答案中没有看到的一种技术：
$val = strval(@$arr["notfound"]); // will not generate errors and
// defaults to an empty string
This is super handy for $_GETparameter loading to keep things short and readable. Bonus, you can replace strval()with trim()... or with intval()if you only accept integers.
这对于$_GET参数加载来说非常方便，可以使内容简短易读。奖励，您可以替换strval()为trim()... 或者intval()如果您只接受整数。
The default for intvalwill be 0if missing or a non-numeric value. The default for strvalis ""if empty, null or false.
默认intval将是0，如果丢失或者非数字的值。默认strval是""如果为空，空或假的。
$val_str = strval(@$_GET['q']);
$val_int = intval(@$_GET['offset']);
Now for an array, you'll still need to loop over every value and set it. But it's very readable, IMO:
现在对于数组，您仍然需要遍历每个值并设置它。但它非常易读，IMO：
$arr = Array (1, 4, "0", "V", null, false, true, 'true', "N");
foreach ($arr as $key=>$value) {
$arr[$key] = strval($value);
}
echo ("['".implode("','", $arr)."']");
Here is the result:
结果如下：
['1','4','0','V','','','1','true','N']
['1','4','0','V','','','1','true','N']
Interesting is that truebecomes "1", but 'true'stays a string and that falsebecomes and empty string "".
有趣的是它true变成了“1”，但'true'仍然是一个字符串，然后false变成了空字符串""。
Now the same data using $arr[$key] = intval($value);produces this result:
现在使用相同的数据$arr[$key] = intval($value);产生这个结果：
['1','4','0','0','0','0','1','0','0']
['1','4','0','0','0','0','1','0','0']
回答by Vivek Pipaliya
Use this function. This will replace null to empty string in nested array also
使用此功能。这也将在嵌套数组中将 null 替换为空字符串
$arr = array(
"key1"=>"value1",
"key2"=>null,
"key3"=>array(
"subkey1"=>null,
"subkey2"=>"subvalue2"),
"key4"=>null);
echo json_encode(replace_null_with_empty_string($arr));
function replace_null_with_empty_string($array)
{
foreach ($array as $key => $value)
{
if(is_array($value))
$array[$key] = replace_null_with_empty_string($value);
else
{
if (is_null($value))
$array[$key] = "";
}
}
return $array;
}
Output will be :
输出将是：
{
"key1": "value1",
"key2": "",
"key3": {
"subkey1": "",
"subkey2": "subvalue2"
},
"key4": ""
}
Try online here : https://3v4l.org/7uXTL
在线尝试：https: //3v4l.org/7uXTL
回答by ayush
foreach($array as $key=>$value)
{
if($value===NULL)
{
$array[$key]="";
}
}
回答by R. Gurung
This can be solved in one line using:
这可以在一行中使用以下方法解决：
array_walk($array_json_return,function(&$item){$item=strval($item);});
here $array_json_return is the array.
这里 $array_json_return 是数组。
