doesn't while loop work correctly in PHP? - php

Question

I want to get the count of characters from the following words in the string. For example, if my input is I am John then the output must be like this:
1 // count of 'I'
4 // count of 'I am'
9 // count of 'I am John'
I use the code like this in PHP for this process:
$string = 'I am John';
$words = explode(' ',$string);
$count_words = count($words);
$i =0;
while ($i<=$count_words){
$word_length =0;
$k=0;
while($k<=$i){
$word_length = strlen($words[$k-1]);
$word_length = $word_length + strlen($words[$k]);
$k++;
}
$word_length = $word_length + $i; // there is "$i" means "space"
echo $word_length.'<br/>';
$i++;
}
But it return the output like this:
1
4
8
7
Why ? Where is my error ? What does my code must be like ?
Thanks in advance!

Answer 1

<?php
$string = 'I am John';
$words = explode(' ',$string);
$count_words = count($words);
$i =0;
while ($i<$count_words){
if($i==0) {
$wordsc[$i] = strlen($words[$i]);
} else {
$wordsc[$i] = strlen($words[$i])+1+$wordsc[$i-1];
}
echo $wordsc[$i]."<br>";
$i++;
}
?>

Answer 2

Your error is here:
$i =0;
while ($i<=$count_words){
//....
}
$count_words is 3, but you iterate 4 times because of <=. Use < instead.

Answer 3

You were looping through to many words. When you use count it returns the number of elements in an array. Remember an array starts at 0.
$word_length + strlen($words[$k - 1]); // You were subtracting 1 I think you were trying to cater for the count offest but you are subtracting -1 from 0 causing the first word to be missed.
CODE SNIPPET START
//Set up the words
$string = 'I am John';
$words = explode(' ',$string);
$count_words = count($words);
//Loop through the words
$i =0;
while ($i<$count_words){
$word_length =0;
$k=0;
$debugString = '';
//Loop through all the previous words to the current
while($k<= $i){
//dont really need this since were adding the word length later
//$word_length = strlen($words[$k]);
//if you -1 from 0 you will get an undefined offest notice. You
//want to look at your current word
$word_length = $word_length + strlen($words[$k]);
//A bit of debugging you can delete this once you have seen the results
$debugString = $debugString ." ".$words[$k];
$k++;
}
$word_length = $word_length + $i ; // there is "$i" means "space"
//Added the debugString for debugging so remove it once you have seen the results
echo $word_length." " .$debugString.' <br/>';
$i++;
}
CODE SNIPPET END

Answer 4

I am happy to provide you with a completely different approach for generating your desired data in a very direct way. (Demo of what is to follow)
var_export(preg_match_all('/ |$/','I am John',$out,PREG_OFFSET_CAPTURE)?array_column($out[0],1):'failure');
Output:
array (
0 => 1,
1 => 4,
2 => 9,
)
Determining the length of each word-incremented substring is effectively the same as determining the offset of each trailing space, or on the final word - the full string length.
preg_match_all() has a built-in "flag" for this: PREG_OFFSET_CAPTURE
preg_match_all() before any array manipulation will output this:
array (
0 =>
array (
0 =>
array (
0 => ' ', // <-- the space after 'I' matched by ' '
1 => 1,
),
1 =>
array (
0 => ' ', // <-- the space after 'am' matched by ' '
1 => 4,
),
2 =>
array (
0 => '', // <-- the end of the string (after 'John') matched by '$'
1 => 9,
),
),
)
array_column() is used on the $out[0] to extract only the offset values (omitting the useless blank and empty strings).
Here is another, totally different method:
array_reduce(preg_split('/(?= )/',$string),function($carry,$item){echo $carry+=strlen($item)," "; return $carry;},0);
output: 1 4 9
This splits the string on the "zero-width" string that is followed by a space. This means that in the exploding process, the spaces are not lost -- this maintains the string and substring lengths for simple addition.