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IWETHEY Home / IWETHEY Board / Theory and Practice of Programming Forum / It's an index vs. value thing.
Post #316,563
by static
Picture of static
11/1/09 7:49:15 AM
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New It's an index vs. value thing.
array_key_exists() and isset() both look at the array's key, which *is* the hash-table lookup. It's wicked fast: probably the fastest thing you can do with an array in PHP.

in_array() looks in the array's *values*. These are *not* in a hash-table and is therefore much much much slower.

Wade, who is paid to know this stuff.
Q:Is it proper to eat cheeseburgers with your fingers?
A:No, the fingers should be eaten separately.
Post #316,565
by drook
Picture of drook
11/1/09 8:35:15 AM
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New Ahh, but look at my corrected* version
You're checking if the array key exists in the second dimension of the array. I'm checking for the value in the first dimension. Both versions are looking at the same hash.


* I had the parameters reversed until I just now updated it.
--

Drew
Post #316,567
by crazy
11/1/09 9:06:41 AM
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New Why is this an argument?
in_array == bad for large sets.
Dead end on this path.
Post #316,578
by drook
Picture of drook
11/1/09 10:33:30 AM
Reply
New Because I didn't read all the comments on that thread
Which I now have. So I now understand that the keys are indexed, but the values are not.
--

Drew
Post #316,581
by crazy
11/1/09 10:37:36 AM
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New Good
I love educational threads.
Post #316,583
by folkert
Picture of folkert
11/1/09 10:56:21 AM
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New Thank you...
Sister Barry Catherine.

Please no rulers today!
Post #316,589
by crazy
11/1/09 11:43:49 AM
Reply
New I prefer the gentle approach
Like my daughter says to me all the time:

GET OUT OF MY HEAD!

I never tell her what to do or think. But little anecdotes and hints are enough to send the wheels spinning. She hates that.
     PHP vs Perl questions - (crazy) - (17) - Oct. 30, 2009, 11:58:10 AM EDT
         Ooops, - (crazy) - Oct. 30, 2009, 12:14:34 PM EDT
         Try this - (drook) - (15) - Oct. 30, 2009, 07:26:19 PM EDT
             Here's a better version. - (static) - (14) - Oct. 30, 2009, 06:54:39 PM EDT
                 Why better? - (drook) - (13) - Oct. 30, 2009, 07:28:35 PM EDT
                     Well, it depends on what defined() means in PERL. - (static) - (12) - Oct. 31, 2009, 08:42:50 AM EDT
                         So two issues - (drook) - (11) - Oct. 31, 2009, 11:12:47 AM EDT
                             That's the problem - (crazy) - (10) - Oct. 31, 2009, 12:09:17 PM EDT
                                 *All* arrays in PHP are hashes - (drook) - (9) - Oct. 31, 2009, 12:58:08 PM EDT
                                     Big difference - (crazy) - Oct. 31, 2009, 04:32:23 PM EDT
                                     Multiple orders of magnitude difference - (crazy) - (7) - Oct. 31, 2009, 04:50:57 PM EDT
                                         It's an index vs. value thing. - (static) - (6) - Nov. 1, 2009, 07:49:15 AM EST
                                             Ahh, but look at my corrected* version - (drook) - (5) - Nov. 1, 2009, 08:35:15 AM EST
                                                 Why is this an argument? - (crazy) - (4) - Nov. 1, 2009, 09:06:41 AM EST
                                                     Because I didn't read all the comments on that thread - (drook) - (3) - Nov. 1, 2009, 10:33:30 AM EST
                                                         Good - (crazy) - (2) - Nov. 1, 2009, 10:37:36 AM EST
                                                             Thank you... - (folkert) - (1) - Nov. 1, 2009, 10:56:21 AM EST
                                                                 I prefer the gentle approach - (crazy) - Nov. 1, 2009, 11:43:49 AM EST

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