Checking for a string in array and add

How can i chec开发者_如何学Pythonk if a string is already present withing an array before adding to it in php?

say if array is $value

$value[0]="hi";
$value[1]="hello"; 
$value[2]="wat";

I want to check if value exists in it before adding it to it.

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$s='hi';
if (!in_array($s, $value)) {
    $value[]=$s;
}

• in_array() checks if that value (1st parameter) is in the array (2nd parameter), returns boolean (! negates it)

• $value[]=$s will add the value to the array with the next index

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There is another tricky way if you want to add a bunch of values into an array, but only if they are not there yet. You just have to organize these new values into another array and use a combination of array_merge() and array_diff():

//your original array:
$values=array('hello', 'xy', 'fos', 'hi');
//the values you want to add if they are not in the array yet:
$values_to_add=array('hi', 'hello', 'retek');

$values=array_merge($values, array_diff($values_to_add, $values));
//$values becomes: hello, xy, fos, hi, retek

---

You can use in_array($searchstring, $array)

in_array("hello", $value) returns true

in_array("hllo", $value) returns false

http://php.net/manual/en/function.in-array.php

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http://php.net/manual/en/function.in-array.php

if(in_array("hello", $value)) { // needle in haystack
   return TRUE;
}

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in_array - Checks if a value exists in an array.

In case of in_array($searchstring, $array), remember, the comparison is done in a case-sensitive manner, if the $searchstring is a "String"

Example :

 - in_array("wat", $value) returns true
 - in_array("what", $value) returns false.

 // Observe carefully
 - in_array("WAT", $value) returns false.

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if you're going to create a Set, it's much better to use array keys instead of values. Simply use

$values["whatever"] = 1;

to add a value, no need to check anything.