comparing a string, and, a string with only numbers

I am new to php and have been trying with no success to get this comparison working:

I have a variable 'productCode' that might hold

Case 1: initially a value of 'Choose'.

Case 2: Later the variable can take a string (with only numbers in it) like 102,103

I need to know what is in the variable productCode? Is it still 'Choose' or '102' (like string with only numbers)

What comparison operator should I use?

Is it having the value 'Choose'? It should be

true if the productCode was set to 'Choose' and

false if it was some other string (with only numbers in it like 102,103..)

I tried

if(strcmp($productCode,'Choose')){

}//tried double quotes also

if(($productCode=='Choose')){

}//tried double quotes also

if(($productCode==='Choose')){

}//tried double quotes also

I am stumbled at this.. '102' compared with 'Choose' is also passing the if statement...

Can someone please help me with a correct method of checking this mixed case..

Edit 1: The related code (after incorporating the === 0 suggesion by Rizier123 :

 $productCode11=$_POST['productCode11'];
 $productCode12=$_POST['productCode12'];
 $productCode13=$_POST['productCode13'];

if(strcmp($productCode11,'Choose') === 0){
    //testing the values if they actually hold what I am expecting
    echo '<script type="text/javascript">alert(" '.$productCode11.' ");</script>';
    echo '<script type="text/javascript">alert(" '.$productCode12.' ");</script>';
        //testing if the 'if' check passes
    echo '<script type="text/javascript">alert("same");</script>';
        $productCode11Error="Fill This";
        $incomplete=true;
    }

if(strcmp($productCode12,'Choose') === 0)){
        $productCode12Error="Fill This";
        $incomplete=true;
    }

if(strcmp($productCode13,'Choose') === 0){
        $productCode13Error="Fill This";
        $incomplete=true;
    }

Edit 2 I did some tests and these are the strange results I got:

$test = strcmp($productCode11, 'Choose');
$test2 = strcmp($productCode11, $productCode12);

if both are 'Choose' I get 1 and it is incremented by 1 for every submission (2,3,4,5...)
if both are numbers and same, I get 0
if LHS is number and RHS is 'Choose', I get -1
if LHS and RHS are 'Choose' I get 1,3,4..
if LHS is 'Choose' and RHS is number I get 1
if both are numbers, and LHS > RHS I get 1
if both are numbers and RHS > LHS I get -3

---

Your first attempt just works as it should. But you have to know, that strcmp() return 0, when the strings are equal, so just add a comparison, eg

if(strcmp($productCode, 'Choose') === 0) {
                                //^^^^^ See here

}

So with this it will evaluate as TRUE if $productCode is equal to "Choose" .

Sidenote:

strcmp() is case-sensitive, means: aA != aa

strcasecmp() is case-insensitive, means aA == aa

---

After a long trial and error, I suspected that the variables returning from $POST are probably having some extra characters. To address this I tried using trim() function. Surprisingly everything started working 'AS EXPECTED'.

(And I am sticking to the === 0 suggestion by Rizier123)

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