How can I split a string into three word chunks? - php

Question

I need to split a string in every three words using PHP
"This is an example of what I need."
The output would be:
This is an
is an example
an example of
example of what
of what I
what I need
I have this example with Java
String myString = "This is an example of what I need.";
String[] words = myString.split("\\s+");
for (int i = 0; i < words.length; i++) {
String threeWords;
if (i == words.length - 1)
threeWords = words[i];
else if(i == words.length - 2)
threeWords = words[i] + " " + words[i + 1];
else
threeWords = words[i] + " " + words[i + 1] + " " + words[i + 2];
System.out.println(threeWords);
}

Answer 1

Solution that use explode, array_slice and implode.
$example = 'This is an example of what I need.';
$arr = explode(" ",$example);
foreach($arr as $key => $word){
//if($key == 0) continue;
$subArr = array_slice($arr,$key,3);
if(count($subArr) < 3) break;
echo implode(" ",$subArr)."<br>\n";
}
Output:
This is an
is an example
an example of
example of what
of what I
what I need.
If you want to suppress the first output with This, remove the comment in the line
//if($key == 0) continue;
If the example can have less than 3 words and these should be output then the line with the break must be as follows:
if(count($subArr) < 3 AND $key != 0) break;
For strings that are not only separated by single spaces, preg_split is recommended. Example:
$example = "This is an example of what I need.
Sentence,containing a comma and Raphaël.";
$arr = preg_split('/[ .,;\r\n\t]+/u', $example, 0, PREG_SPLIT_NO_EMPTY);
foreach($arr as $key => $word){
$subArr = array_slice($arr,$key,3);
if(count($subArr) < 3) break;
echo implode(" ",$subArr)."<br>\n";
}
Output:
This is an
is an example
an example of
example of what
of what I
what I need
I need Sentence
need Sentence containing
Sentence containing a
containing a comma
a comma and
comma and Raphaël

Answer 2

To include only words (notice the fullstop is removed from the last trigram), use str_word_count() to form the array of strings.
Then you need to loop while there are three elements to print.
Code: (Demo)
$example = 'This is an example of what I need.';
$words = str_word_count($example, 1);
for ($x = 0; isset($words[$x + 2]); ++$x) {
printf("%s %s %s\n", $words[$x], $words[$x + 1], $words[$x + 2]);
}
Output:
This is an
is an example
an example of
example of what
of what I
what I need
If you don't like printf(), you could echo implode(' ', [the three elements]).
If you want to print a single string of words when there are less than 3 total words in the string, then you could use a post-test loop. Demo
And then, of course, if we going to stumble down the rocky road of "what is a word", then an ironclad definition of "what is a word" will need to be defined and then a regex (potentially with multibyte support) will need to be suitably crafted. Basic Demo