Unable to find tokens in string

Question

I am trying to write a small php application and i am facing a problem. This is suppose to get text like :

this is *noun but it is *name.

And should take the words that start with a star and add them to the string tokens. However this is not working.

// get list of fields (each should have words delimited by underscores
$storyArray = split(' ', $story);
$tokens = ""; // space-delimited list of fields
for ($i = 0; $i < count($storyArray); $i++) {
    if ($storyArray[$i][0] == '*')
     $tokens .= $storyArray[$i] + " ";
}
$tokensArray = split(' ', $tokens);

Answer 1

On your if statement, change:

if ($storyArray[$i][0] == '*')

To:

if ($storyArray[$i]{0} == '*')

Answer 2

This worked for me:

$story = "this is *noun but it is *name";

$storyArray = split(' ', $story);
$tokens = array();
for ($i = 0; $i < count($storyArray); $i++) {
  if ($storyArray[$i][0] == '*') {
    array_push($tokens, substr($storyArray[$i], 1));
  }
}
var_dump($tokens);
$tokenString = implode(" ", $tokens);

Note that I'm pushing the tokens directly into an array, then imploding it.

Answer 3

Wow, I can't believe I've been debugging this and missing the obvious fault!

This line here:

$tokens .= $storyArray[$i] + " ";

You must concatenate with a period (.), not a plus sign! What you have right now is basically the same as $tokens .= 0;

Answer 4

"+" is for addition, not string concatenation. It casts its arguments as numbers, which will always be 0 in your source.

On another note, splitting $tokens is unnecessary. Instead, append tokens to $tokensArray:

$story = "this is *noun but it is *name";
// get list of fields (each should have words delimited by underscores
$storyArray = split(' ', $story);
$tokens = ""; // space-delimited list of fields
$tokensArray=array();
for ($i = 0; $i < count($storyArray); $i++) {
    if ($storyArray[$i][0] == '*') {  
        $tokens .= $storyArray[$i] . " ";
        $tokensArray[] = $storyArray[$i];
    }
}

If you only needed $tokens for generating $tokensArray, you can get rid of it. Also, depending on whether you need $storyArray, preg_match_all(...) might be able to replace your code:

preg_match_all('/\*\w+/', $story, $tokensArray);
$tokensArray = $tokensArray[0];

Answer 5

Replace

$tokens .= $storyArray[$i] + " ";

with

$tokens .= $storyArray[$i]." ";

And

$tokensArray = split(' ', $tokens);

with

$tokensArray = split(' ', rtrim($tokens));

Answer 6

You can also use a regular expression to achieve the same effect, without all the string manipulation you are doing right now. This would be the most elegant solution:

$string = "this is *noun but it is *name";

// Lets set up an empty array
$tokens = array();

preg_match_all('/\*\w+/m', $string, $tokens);
$tokens = $tokens[0]; // Only one sub-pattern, dropping unnecessary dimension.

var_dump($tokens);

Regular expressions exists to do mainly exactly the kind of task you are trying to achieve now. They are usually faster than doing string manipulations manually (Regular Expression engine in PHP is compiled code).

To explain my regex:

• /: start boundary
• \*: an asterisk (*)
• \w: any alpha-numeric character or underscore
• +: previous marker, 1 or more times. (match \w one or more times)
• /: end boundary
• m: multiline modifier

Answer 7

$tokens .= $storyArray[$i] + " ";

in this line, you should be using the . operator to concatenate strings.