Determine if an array contains a certain value

No searching is required, just access the element using ordinary array indexing.

if ($a[0] == 1.10) {
    echo "Yes";
}

Use this code:

<?php
$a = array(1.10, 12.4, 1.13);
if($a[0] == "1.10"){
 echo "Yes";
}
?>

You just need a minor adjustment in your in_array PHP function usage:

<?php
$a = array(1.10, 12.4, 1.13);

if (in_array(1.10, $a)) {
    echo "Yes";
}

Output:

Yes

$a = array(1.10, 12.4, 1.13);

if (array_search('1.10', $a) === TRUE) {
    echo "Yes";
}

This sounds like a job for array_search

which is used in the following manner:

<?php
$array = array(0 => 'blue', 1 => 'red', 2 => 'green', 3 => 'red');

$key = array_search('green', $array); // $key = 2;
$key = array_search('red', $array);   // $key = 1;
?>

If it is in the data, $key is given the corresponding value of the element that contains the data you are searching for.

You need to learn proper syntax. Try:

if ( in_array('1.10', $a) ) {
    echo "Yes";
}


//syntax
bool in_array ( mixed $needle , array $haystack [, bool $strict = FALSE ] )

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

1- if you know the index then you can simply do:

if($array[$index] == '1.10'){

}

2- if you want to search for a value if exists in the array:

if(in_array("1.10", $array)){

}

3- if you want to find key for a given value:

   $key = array_search("1.10", $array);

To just search the first element in the array:

if ($a[0] == "1.10") { echo "Yes"; }

Or to search the whole array:

if (in_array("1.10", $a)) { echo "Yes"; }

Use this code:

<?php
$a = array(1.10, 12.4, 1.13);

$isExists = in_array(1.10, $a) ? "Exists" : "Not Exists";

echo $isExists;
?>

Use this code:

<?php
$a = array(1.10, 12.4, 1.13);
echo ($a[0] == "1.10")? "Yes" :"";
?>

You can use aray_search it returns the corresponding key if successful.

$a = array(1.10, 12.4, 1.13);

if (array_search('1.10',$a) !== false) {
    echo "Yes";
}

output:

Yes

you can speed up the function by turning on the strict mode:

it returns the corresponding key if successful.

$a = array(1.10, 12.4, 1.13);

if (array_search('1.10',$a,true) !== false) {
    echo "Yes";
}

output:

Yes