Count duplication

happyjourney

Hi,

I have a script that write log id number to a text file. I have written a script to read the data line by line. What I need to accomplish is to count the number of time the id is repeated. Example of data is listed below: thanks for your help.

37775
35707
37450
28105
28105
35527
28223
28224
28372
28373
36730
38144
37581
36201
38154
22341
36834
36540
37992
31305
26570
31662
35743
37397
36208
37592
37771
11681
30640
30640
20
37985
35792
37594
36316
24
37434
37461
37598
36866
35618
29135
29135
29135
36867
37145
37136
29135
29129
29135
37601
6105
31662
6092
6239
6095
6108

leatherback

hi,

It depends a little on how you need the info..

The easiest would be to -during reading- store the data in an array, where the KEY is the value you read, and the VALUE is a count of the number:

in your read loop:

if(array_key_exists($value, $array))
  {
  $array[$value]++;
  }
else
  {
  $array[$value] = 1;
  }

Weedpacket

[man]file[/man] to read the file.
[man]trim[/man] to trim off the linebreaks on the end (in case the last number doesn't have one; otherwise it would be counted as different even if it's not).
And the finale: [man]array_count_values[/man] to count the different values in the array.

leatherback

Weedpacket wrote:
And the finale: [man]array_count_values[/man] to count the different values in the array.

shoop! will you believe I even checked the man to make sure there was no such function in php 🙁

happyjourney

Thank you, but i am so new to programming script. I will do more finding to understand your responses. Do I need to put the array_key_exists in the for loop to check for each value. I would like to echo out in the format as ID-count.

leatherback

Hi Happy,

You should follow weedpackets advice. Although he links himself to mind-numbing substances, he is actually well-versed in php programming, and the authority on the board.

Give it a crack with the links that he gave you, and show us how you go. (It is easy to give you a piece of code, but it will not help you in the long run).

Give it a stab, and let us know where you are stuck.

happyjourney

thnkx

Weedpacket

leatherback wrote:
shoop! will you believe I even checked the man to make sure there was no such function in php

There is a tradeoff; array_count_values is a lot faster than the counting-while-reading but it would have at least twice the memory requirements, probably much more if there are a lot of duplicates. As ever, though, that's really only an issue if the list is REALLY large, like on the order of millions of records.