parse a string for certain words

[Mosher]

Hi all, I was wondering if php can parse a text string for certain words and
return "true" if that word is found. For example, I have a string like this:

$string = "The rain in spain is the same as the rain on the plain";

I want to run a php command(s) that will parse the sentence and return true
if, for example, the word "spain" is found.

Any ideas?

Thanks,

Mosher

[NC]

Mosher wrote:

I was wondering if php can parse a text string for certain words and
return "true" if that word is found.

You shouldn't be wondering. Reading The PHP Manual is considered
by many to be a more efficient use of time. This should get you
started:

http://www.php.net/strpos

Cheers,
NC

[John Dunlop]

Mosher wrote:

Hi all, I was wondering if php can parse a text string for certain words and
return "true" if that word is found. For example, I have a string like this:

$string = "The rain in spain is the same as the rain on the plain";

I want to run a php command(s) that will parse the sentence and return true
if, for example, the word "spain" is found.

preg_match('`\bspain\b`',$subject)

Explanation: Match 'spain' if the characters before and
after are not word characters, where 'word characters' are
letters, numbers and underscores. Or you could make your
own assertions; e.g.,

`(?<![a-zA-Z-])spain(?![a-zA-Z-)`

matches 'spain' where the characters before and after are
not US-ASCII letters or hyphens.

Make the pattern case insensitive by setting the i modifier.

preg_match('`(?<![a-zA-Z-])spain(?![a-zA-Z-)`i',$subject)

--
Jock

[zeldorblat]

Both strpos() and preg_match() will work, but in this case strpos() is
preferred for performance reasons. From
<http://www.php.net/manual/en/function.preg-match.php> :

"Tip: Do not use preg_match() if you only want to check if one string
is contained in another string. Use strpos() or strstr() instead as
they will be faster."

[Mosher]

NC, you shouldn't assume that I didn't do some preliminary reading...Your
sarcasm to what appears to be a simple question is unnecessary. A simple
"check out strpos" would have been sufficient...

Thanks anyway,

Mosher
"NC" <[e-mail]> wrote in message
news:11**********************@z14g2000cwz.googlegr oups.com...

Mosher wrote:

I was wondering if php can parse a text string for certain words and
return "true" if that word is found.

You shouldn't be wondering. Reading The PHP Manual is considered
by many to be a more efficient use of time. This should get you
started:

http://www.php.net/strpos

Cheers,
NC

[John Dunlop]

ze********@gmail.com wrote:

Both strpos() and preg_match() will work, but in this case strpos() is
preferred for performance reasons.

I'm sure the difference in speed is noticeable, so thank you
for bringing it up.

The point here, though, was to match words out of a string
(a sentence), not strings out of a string. Since strpos()
cannot tell a word from a string, regular expressions are a
better choice.

--
Jock

[ZeldorBlat]

You are correct, and preg_match does give you a bit more versatility.

One could also use explode() and in_array to search for words in some
sort of delimited string (like a sentence where the delimiter is a
space). Something like:

$string = "The rain in spain is the same as the rain on the plain";
$searchWord = "spain";
return in_array($searchWord, explode(" ", $string));

[John Dunlop]

ZeldorBlat wrote:

One could also use explode() and in_array to search for words in some
sort of delimited string (like a sentence where the delimiter is a
space). Something like:

$string = "The rain in spain is the same as the rain on the plain";
$searchWord = "spain";
return in_array($searchWord, explode(" ", $string));

Remember that while exploding the string on a single
character should work for simple sentences, such as 'The
rain in Spain ... ', it will likely fail for more complex
ones containing internal punctuation, such as the one you're
reading now.

Another difficulty with parsing sentences into words is that
the hyphen might be part of a word or it might join compound
adjectives, which you might consider separate words.

--
Jock

[Mosher]

Hey guys, thanks. I used the explode() function and it worked for this
example.

Just an FYI, using the explode() method is space delimited, so if I had a
string like: "the rain in spain is the same as st paul", st paul would be
two elements in the array, not one.

Mosher

"Mosher" <mo***********@yahoo.com> wrote in message
news:fP********************@comcast.com...

Hi all, I was wondering if php can parse a text string for certain words
and return "true" if that word is found. For example, I have a string like
this:

$string = "The rain in spain is the same as the rain on the plain";

I want to run a php command(s) that will parse the sentence and return
true if, for example, the word "spain" is found.

Any ideas?

Thanks,

Mosher

[ZeldorBlat]

Explode also allows you to specify a string to use for the boundaries.
Unfortunately, you can't say something like "explode using either a
space or a newline as the seperator." However, you can use strtok() in
this situation:

http://www.php.net/manual/en/function.strtok.php

It will tokenize the string splitting it on any single character from
the second parameter ("token"). You can even change your delimiters
with each call to strtok. This might also save you some time because
if you only care whether any word exists in a string, you can quit as
soon as you find it. Something like this (a contrived example, of
course):

$string = "The rain-in*spain is the same as the rain-on*the-plain";
$matches = array("rain", "spain", "plain");
$delims = " -*";

$tok = strtok($string, $delims);
while($tok) {
if(array_search($tok, $matches) !== false)
return true;
}
return false;