Find a value in an array [closed]

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开发者_运维技巧

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What I am doing wrong with the following code? I want to compare if the element $my_id is present within the array $arr. If it is present return TRUE else return FALSE.

for($i=0;$i<$cnt;$i++)
{
    if($arr[$i] == $my_id)
    {
        return TRUE;
    }
    else
    {
        return FALSE;
    }
}

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You could replace that with...

return in_array($my_id, $arr);

...assuming you don't really want to return FALSE if the first element does not match.

If that is actually what you wanted, you could use...

return $arr[0] == $my_id;

If you want to leave your code mostly intact, just move the return FALSE to outside of the loop body.

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The issue you are having is that you aren't looping entirely through the array. You are returning true/false after the first item in the array, irrespective of subsequent array entries after [0]

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Well, I believe you should remove the else statement, unless you always just have one element in the array. I mean -- from the example you're showing, you're exiting the loop with this. I doubt this is what you want.

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If you just need to know, if a value is within a given array

in_array($value, $array);

Maybe you want get the index of (the first occurence of) the value too

$index = array_search($value, $array);
if ($index === false) {
  // Not in array
} else {
  echo $array[$index];
}

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The error in Your code is to return false on $arr[$i] != $my_id. The algorithm should look something like this:

for($i=0;$i<$cnt;$i++)
{
    if($arr[$i] == $my_id)
    {
        return TRUE;
    }
}
return FALSE;

P.S. This isn't the best solution for this problem in PHP language. You should use one from alex.