PHP strpos not getting the expected results

Question

Using strpos(), I'm not getting the results I want. I suspect the problem is in the conditional statements. If the condition is true, everything works fine it seems. But if it is false, the code for the condition true still executes. Here's the code.

<?php
// require_once 'functions/functions.php';
?>

<?php

if (isset($_POST['submit'])) {
    $string = $_POST['sentence'];
    $findString = $_POST['findstring'];
    $strPosition = stripos($string, stringToFind($findString));

 //  if (($strPosition == true) || ($strPosition == 0)) {
if ($strPosition !== true) {  
    echo 'Found!', '<br><br>';
    echo 'In the string ', $string, '.', '<br>';
    echo 'And the word you want to find is ';
    $readStr = substr($string, $strPosition, strlen($findString));
    echo $readStr, '.', '<br>';

    if ($strPosition == 0) {
    echo 'It is at the beginning of the string.', '<br>';
}
else {
    echo 'It is in the ', $strPosition, ' ', 'position.', '<br>';
}
}
else {
    echo 'Not found. Try again.', '<br>';
}
}

function stringToFind($findString)
{
    return $findString = $findString;
}
?>

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>String Position</title>
</head>
<body>

<h1>Finding a string and then read it</h1><br><br>

<form id="form1" class="form" action="<?php echo                         htmlspecialchars($_SERVER['PHP_SELF']); ?>" method="post">
<label for="sentence">Sentence here:
<textarea id="sentence" name="sentence" value="Put a sentence here."></textarea></label>
Enter a string: <input type="text" name="findstring">
<input type="submit" name="submit" value="Go">
</form><br><br>
</body>
</html>

`if ($strPosition !== false)` should be the condition. – Ja͢ck Jul 04 '14 at 12:20 — Ja͢ck, Jul 04 '14 at 12:20

score 2 · Accepted Answer · edited May 23 '17 at 11:57

2

Yes because your condition gets satisfy even if returns false as you have done a loose comparison with 0. Change your below condition

if (($strPosition == true) || ($strPosition == 0)) {

with,

if ($strPosition !== false) {

Helpful: How do the PHP equality (== double equals) and identity (=== triple equals) comparison operators differ?

edited May 23 '17 at 11:57

Community

1
1

answered Jul 04 '14 at 12:21

Rikesh

26,156
14
79
87

Honestly, I still don't fully get the idea of !== but I followed your advice. Unfortunately, the problem is still there. even the answer is false, the instruction to display the message "not found" is still not showing. – Joey Jul 04 '14 at 13:10
`var_dump($strPosition);` & tell us what it is showing. – Rikesh Jul 04 '14 at 13:13
Replicating, var_dump() = boolean false. – Joey Jul 04 '14 at 13:24
And you saying it's still going in if after changing with the condition I provided you in answer ? – Rikesh Jul 04 '14 at 13:47
The problem was that after changing to !==, I didn't change the codeblock for the true condition. Your link is helpful in deed. Now that I think I am learning the difference between == and ===, I would just have to adjust a few statements in my code and I believe I will get what I want eventually. – Joey Jul 04 '14 at 22:55
Hello quick question. Instead of if ($position !== true) {, can I just put if (!$position) {? When I did it worked but I'm concerned if it would still check for the datatype. – Joey Jul 06 '14 at 22:51

score 2 · Answer 2 · edited Jul 13 '14 at 03:18

2

from the php manual:

Returns the position of where the needle exists relative to the beginnning of the haystack > string (independent of offset). Also note that string positions start at 0, and not 1. Returns FALSE if the needle was not found.

change this if condition

if (($strPosition == true) || ($strPosition == 0)) {

to

if ($strPosition !== false) {

edited Jul 13 '14 at 03:18

Harpreet Singh

2,651
21
31

answered Jul 04 '14 at 12:21

BeBest

319
1
3
9

PHP strpos not getting the expected results

2 Answers2