尝试从函数中设置变量，并在同一行中检查它是否为false

I am trying to set a variable from a function, and then check if it is false in the same line. If it is false, I want to execute some code.

The code I have is the following:

  if ($wordid = wordnet_get_wordid_from_word($word) == FALSE) {
db_set_active();
    return $word;
  }

However it appears that $wordid is not getting set by this.

I've seen something like this being used before, and I've tested that inside the function, the value returned is NOT empty.

So what am I doing wrong here? Is it not possible to set a variable on the same line as you check whether it is false?

$wordis is getting set in this code. If you do an echo gettype($wordis) after the if you'll find it's a boolean. It's value will be the outcome of evaluating this: wordnet_get_wordid_from_word($word) == FALSE. Remember, if that evaluates false it'll skip the if statement anyway, that's probably why you think it's not working.

If you want $wordid = wordnet_get_wordid_from_word($word) and to check if that's false, use brackets:

if (($wordid = wordnet_get_wordid_from_word($word)) == FALSE) {..

IMO, confusing code. Separate it out.

Simple:

function test() {
    return false;
}

if( !$var = test() ) {
    echo "it's false";
} else {
    echo "it's true";
}

Output: it's false

Is it not possible to set a variable on the same line as you check whether it is false?

The above shows that it can be done.

Another example:

function hello() {
    return 'hello';
}

if( !$var = hello() ) {
    echo "it's false" . PHP_EOL;
} else {
    echo "it's true" . PHP_EOL;
}


var_dump( $var );

Outputs: it's true string(5) "hello"