Why can't I use the '@' operator inside of strings?

Question

I have a variable that sometimes doesn't exist that I want to use inside of a string (or heredocs).

My code is like this:

if(someExternalThings()) {
    $variable = 'value';
}

echo "I have a {$variable}";

The code works fine when someExternalThings() is true, but if it doesn't, PHP throws an error, as expected.

Since I know that variable won't break anything (other than inside of the strings) I decided to add @ before it.

echo "I have a {@$variable}";

But it outputs: I have a {@} and throws an error.

I fixed this by doing this:

$variable = @$variable;
echo "I have a {@$variable}"

//outputs: I have a {@} and throws no errors

Or by putting the entire echo inside of the if that checks someExternalThings()

if(someExternalThings()) {
    $variable = 'value';
    echo "I have a {$variable}";
}

This kinda confuses me since we can use these...

echo "{$foo->bar[0]}";
echo "{${foo::bar}}";

...and it just works fine.

What do you mean by full stop, @treyBake? Anyways, I figured that it would save some lines if I do that since the missing variable is harmless, it's just for appending some extra info or some sort in the string. — , Oct 15 '19 at 08:38
Never suppress errors - it's bad practice. Fix them instead. .. — treyBake, Oct 15 '19 at 08:39
It kinda smells bad to use ```@```, but using it like ```echo @"{$foo}"``` seems to do the trick. — Kyrre, Oct 15 '19 at 08:40
@Kyrre then why the "but using it seems to do the trick" comment? o.O — treyBake, Oct 15 '19 at 08:42
Cus that's what OP asked for??? I'm not the morality police. — Kyrre, Oct 15 '19 at 08:43
I don't know where I learned this, but suppressing errors aren't "evil" if you know how to deal with them. My problem in my code is fixed anyway and I'm just asking **why** we can't use `@` inside of strings. @Kyrre's comment works, btw — , Oct 15 '19 at 08:46
@0x4kgi [debugging agony](https://stackoverflow.com/questions/136899/suppress-error-with-operator-in-php) — lovelace, Oct 15 '19 at 08:55
@0x4kgi yes it is, if you know how to deal with them - fix them. — treyBake, Oct 15 '19 at 08:58

score 1 · Accepted Answer · answered Oct 15 '19 at 09:06

The use of '@' for 'silence errors' does not work for variables inside a string. It would work at the start of the statement, but it's much better to avoid the issue.

If you want to avoid an 'unknown variable' notice, you can set it to something. For example:

<?php
$variable = '';
if(someExternalThings()) {
    $variable = 'value';
}
// now $variable always has a value, maybe empty, but it exists.

echo "I have a {$variable}";

If the echo should only happen when $variable has a value, then put it into the if condition.

Why can't I use the '@' operator inside of strings?

1 Answers1