Add +1 to each index found in an array - php

Question

I have a form that takes in a users input and puts it in an array, the user then chooses a word they want to find in said array. Thereafter the array is checked to see what each index of the word is as well as each occurrence of the word in the text.
So if you write the string "What is what" and want to find the word "what" it will say that the position of the word is "0 and 2" whereas I'd like it to say "1 and 3". How do I go about this?
Here's the code:
<form action="sida3.php" method="post">
Text: <textarea name="textarea"></textarea>
<br> Search word: <input type="text" name="search">
<br>
<input type="submit" name="submit" value="Submit">
</form>
<?php
if(isset($_POST['submit'])){
$parts = explode(" ", $_POST['textarea']);
$strName = $_POST['search'];
print_r ($parts);
echo '<br>';
foreach($parts as $item) {
if ($item == $strName) {
$counter++;
}
}
echo "The word $strName can be found at: ";
echo implode(' ', array_keys($parts, $strName));
echo "<br>";
echo "The word $strName was found $counter times";
}

Answer 1

I'm not sure what you're doing with the foreach or if that's where you want to create the positions, but:
foreach($parts as $pos => $item) {
if ($item == $strName) {
$result[] = $pos + 1;
}
}
Then just:
echo implode(' ', $result);

Answer 2

You can map +1 over the array keys before imploding. I also suggested another way to find the search term and count the occurrences, if you're interested in that, but map will work with the way you're currently doing it as well.
$found = array_intersect($parts, [$strName]);
echo "The word $strName can be found at: ";
echo implode(' ', array_map(function($x) { return $x + 1; }, array_keys($found)));
echo "<br>";
echo "The word $strName was found ". count($found) ." times";

Answer 3

You can use array_combine to combine a range from 1 to count of the array with the values.
$str = "This is a string.";
$arr = explode(" ", $str);
$range = range(1,count($arr)); // creates a range from 1 -> count of $arr
$new = array_combine($range, $arr); // sets the range as the key and $arr as the value
var_dump($new);
https://3v4l.org/SUhVM
Now that I look at the question again I see that there is a big flaw we all have missed.
If the word you search for is next to a dot, comma or other symbol it won't be counted.
Here I use the code I had in the answer above but added preg_replace to remove all characters that is not a-Z 0-9 (meaning english alphabet, change to suit your needs).
I then use substr_count to find the number of words without looping.
I use array_intersect to reduce the array to only the items matching $find, and grab the keys with array_keys. The key is the positions of the words.
All done without looping.
$str = "This is a car. Automobile (car) is another word for it. You can also add a hashtag, #car";
$find = "car";
$count = substr_count($str, $find);
$str = preg_replace("/[^a-zA-Z 0-9]/", "", $str);
$arr = explode(" ", $str);
$range = range(1,count($arr));
$new = array_combine($range, $arr);
$positions = array_keys(array_intersect($new, [$find]));
echo $find . " was found " . $count . " times. At positions: " . implode(", ", $positions);
Just looping and matching with == will only find one car in this string.
https://3v4l.org/sHAd5