You want to do something with every word in a file. For example, you want to build a concordance of how many times each word is used to compute similarities between documents.
Read in each line with fgets(), separate the line into words, and process each word:
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$fh = fopen('great-american-novel.txt','r') or die($php_errormsg); while (! feof($fh)) { if ($s = fgets($fh)) { $words = preg_split('/\s+/',$s,-1,PREG_SPLIT_NO_EMPTY); // process words } } fclose($fh) or die($php_errormsg); |
This example calculates the average word length in a file:
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$word_count = $word_length = 0; if ($fh = fopen('great-american-novel.txt','r')) { while (! feof($fh)) { if ($s = fgets($fh)) { $words = preg_split('/\s+/',$s,-1,PREG_SPLIT_NO_EMPTY); foreach ($words as $word) { $word_count++; $word_length += strlen($word); } } } } print sprintf("The average word length over %d words is %.02f characters.", $word_count, $word_length/$word_count); |
Processing every word proceeds differently depending on how “word” is defined. The code in this recipe uses the Perl-compatible regular expression engine’s \s whitespace metacharacter, which includes space, tab, newline, carriage return, and formfeed.
The Perl-compatible engine also has a word-boundary assertion (\b) that matches between a word character (alphanumeric) and a nonword character (anything else).
Using \b instead of \s to delimit words most noticeably treats words with embedded punctuation differently.
The term 6 o’clock is two words when split by whitespace (6 and o’clock); it’s four words when split by word boundaries (6, o, ‘, and clock).
