Implode values from array with NULL or empty values cause unexpected output

Question

I am trying to get the following output: ``` string1, string2, string3 ``` Those values comes from `$var1`, `$var2` and `$var3` but they can be `NULL` at some point and here is where my problem is. So far this is what I have: ``` $arr = array( $var1 !== null ? $var1 : '', $var2 !== null ? $var2 : '', $var3 !== null ? $var3 : '', ); echo $arr !== '' ? implode(', ', $arr) : '-'; ``` This are the test I've run: ``` input: array('string1', 'string2', 'string3') output: string1, string2, string3 input: array('string1', 'string2') output: string1, string2 input: array('', '', '') output: , , input: array(null, null, null) output: , , ``` As you may notice if values are coming everything work as I want, if values are coming `NULL` then I am getting `, ,` when I what I want is just a `-`. I have tried to find whether the array contains empty values or not using this code: ``` $cnt = count($arr) !== count(array_filter($arr, "strlen")); echo $cnt; ``` Then I've run the following test: ``` input…

Accepted Answer

Filter the array before implode and if the imploded array is an empty string assign `-`, otherwise assign the imploded array:

```
$result = implode(', ', array_filter($arr)) ?: '-';
```

For PHP < 5.3.0 not supporting `?:` then:

```
$result = ($s = implode(', ', array_filter($arr))) ? $s : '-';
```

Implode values from array with NULL or empty values cause unexpected output

Solution

Problem