Pruning a file

[lorddraco98]

need some advice on the best code to use for this situation. Basically I'm writing a function that has to do the following:
opens a file for reading/writing from a path specified when calling the function

looks over all the data in the file(it's an m3u file, a winamp playlist file with just basically text info about songs) and matches certain songs with those listed in an array.

let me give an exmaple. The m3u file contains info for songs like this:
#EXTINF:100,Artist1- Title1
MP3s\artist1.mp3
#EXTINF:200,Artist2- Title2
MP3s\artist2.mp3
#EXTINF:150,Artist3- Title3
MP3s\artist3.mp3

that's 3 songs right there. Now I have an array of songs that gets passed trough the function as well. The array goes like this:
$deletesongs[0]= "artist1- title1";
$deletesongs[1]= "artist2- title2";

now what I need the function to do is to search all the entries in the m3u file that match the entries in the $deletesongs array and then delete both lines in the m3u file for each of the songs.
So the function should produce the following m3u file after it went through and deleted the 2 entries contained in the array:
#EXTINF:150,Artist3- Title3
MP3s\artist3.mp3

then the m3u file needs to be uploaded back to the server
hope this is not too confusing hehe, any ideas on this?

[diego25]

Well, the function array_diff will return the entries that are not in the array...so all you have to do is get the file into an array that'd work with array_diff.

Diego

[lorddraco98]

allright, but the problem with is if you look at my 2 arrays, they are formatted differently. I don't even know where to begin making the m3u file array the same format as the other array

[diego25]

Ok, the lines in the file that contain the data that you want to compare is on every other line. So you can first use file() to read the entire file, and then use a for loop to create a new array with the data that you want. In this for loop, instead of $i+, you'd use $i +=2 so that you get every other line only. Then, the info you want is after the first comma, so you can use strpos() and substr() to get the artist and song name.

Diego

[lorddraco98]

Originally posted by diego25
Ok, the lines in the file that contain the data that you want to compare is on every other line. So you can first use file() to read the entire file, and then use a for loop to create a new array with the data that you want. In this for loop, instead of $i+, you'd use $i +=2 so that you get every other line only. Then, the info you want is after the first comma, so you can use strpos() and substr() to get the artist and song name.

Diego

thanks Diego, i got it now so I have an array that has just these values:
$array2[0]= #EXTINF:100,Artist1- Title1
$array2[1]= #EXTINF:200,Artist2- Title2
$array2[2]= #EXTINF:150,Artist3- Title3

I'm a little confused now how to make a 3rd array, containing only eg. Artist1- Title1 for each of the 3 values of array2

I looked into those functions you gave, but still am unsure. Anyway you could give me a code example or a little more help?? Thanks a ton!

[diego25]

$array[0] = substr($array[0], strpos($array[0], ',')+1);

The +1 is there so that the comma is not included.

Diego

[lorddraco98]

Originally posted by diego25
$array[0] = substr($array[0], strpos($array[0], ',')+1);

The +1 is there so that the comma is not included.

Diego

wow, sweet, it worked.
Another favor hehe, if you don't mind, could you explain what is happening right there in that code? I don't quite understand how it did what it did hehe
Thanks!!
edit: I figured it out. cleaver coding there hehe
Now, next step is to compare those 2 arrays and be able to delete the 2 lines from that m3u file in the values in the 2 arrays that match. Any ideas on that?
btw, sorry for all the questions

[diego25]

Instead of the deleting the lines, you can overwrite the file with the lines that should be there.

Diego

[lorddraco98]

Originally posted by diego25
Instead of the deleting the lines, you can overwrite the file with the lines that should be there.

Diego

hrm, so if I compare the 2 arrays, it should just leave me with a line like:
artist4- title4
and that's the only line that should stay.
How would I go back into the file and rewrite it with all the m3u data for artist4- title4
like it should write to the m3u:
#EXTINF:150,Artist4- Title4
MP3s\artist4.mp3

btw, I appreciate your help so much with this, you are great bro! Do you have AIM or MSN, I'd love to talk with you on IM sometime!

[lorddraco98]

i tried using array_search and in_array
but for some reason it returned all of the results, as in it didn't find anything different when it should have

[diego25]

Can you post the part of the code in question?

Diego

[lorddraco98]

here's the whole thing Diego.
I have $filearray3 that I now need to compare to $deletesongs
I then need to take only the values in $filearray3 that are not found in $deletesongs and write those back to the m3u file on the server

here's the code:

<?php
//start process m3u function
function prunem3u($deletesongs, $filepath)
{
@$fp= fopen($filepath, "a+");
if (!$fp)
{
echo "Couldn't open file";
exit;
}
@$filearray= file($filepath);
if (!$filearray)
{
echo "couldn't get file";
exit;
}
//echo $filearray[0]."<br>".$filearray[1]."<br>".$filearray[2]."<br>".$filearray[3];
$result= array_diff($deletesongs, $filearray);
//echo "<br>".$result[0];
//echo "<br>".$result[1]."<br>".$result[2]."<br>".$result[3];
$arraynum= count($filearray);
$j=0;
//this is the array with the 1st line only from the m3u file
for ($i=0; $i<=$arraynum; $i+=2)
{
$filearray2[$j]= $filearray[$i];
$j++;
}
$arraynum2= count($filearray2);
for ($i=0; $i<=$arraynum2; $i++)
{
echo $filearray2[$i]."<br>";
}
//this is the artist-title separated out from filearray2
for ($i=0; $i<=$arraynum2; $i++)
{
$filearray3[$i] = substr($filearray2[$i], strpos($filearray2[$i], ',')+1); 
echo $filearray3[$i]."<br>";
}
$result1= array_diff($deletesongs, $filearray3);
$arraynum3= count($result1);
$arraynum4= count($deletesongs);
for ($i=0; $i<=$arraynum4; $i++)
{
echo $deletesongs[$i]."<br>";
}
$k=0;
for ($i=0; $i<=$arraynum2; $i++)
{
if (!array_search($deletesongs[$i], $filearray3))
{
$updatedm3u[$k]= $filearray3[$i];
$k++;
}
}
$arraynum5= count($updatedm3u);
for ($i=0; $i<=$arraynum5; $i++)
{
echo $updatedm3u[$i]."<br>";
}
}
?>

the m3u file and $filearray1 contain:
#EXTINF:100,Artist1- Title1
MP3s\artist1.mp3
#EXTINF:200,Artist2- Title2
MP3s\artist2.mp3
#EXTINF:200,Artist3- Title3
MP3s\artist3.mp3
#EXTINF:200,Artist4- Title4
MP3s\artist4.mp3

and $deletesongs contains:
$deletesongs[0]= "Artist1- Title1";
$deletesongs[1]= "Artist2- Title2";
$deletesongs[2]= "Artist3- Title3";

thank you !

[diego25]

Where you have
$filearray2[$j]= filearray[$i];
around line 50, make it
$filearray2[$j]= trim($filearray[$i]);

The reason is because file() will return the newlines at the end of each line of the file. So later when you're comparing, it will never match because of that extra newline.

Also, change
$result1= array_diff($deletesongs, $filearray3);
to
$result1= array_diff($filearray3, $deletesongs);
Check out array_diff for the reason why.

Then after array_diff, put a
print_r($result1);
to see what array_diff returned. And you'll see that you have to change your next loop to

$k = 0;
foreach ($result1 as $key => $value)

{

if (($j=array_search($value, $filearray3)))

{

$updatedm3u[$k]= $filearray2[$j];

$k++;

}

}

Diego

[lorddraco98]

wow, that's amazing hehe
you are great!
last thing and I will be in debt to you hehe
I now have the array with just this value:
#EXTINF:200,Artist4- Title4

how to I add back in:
MP3s\artist4.mp3

right after #EXTINF:200,Artist4- Title4 ?

so the array should be:
$updatedm3u[0]=
#EXTINF:200,Artist4- Title4 ?
MP3s\artist4.mp3

i tried a few things and they didn't work, i'm sure you have a better way lol
thank you again so much!

[diego25]

That info is in the first array that you've created with file(), right? And, if you look at the indeces, you can probably find a relationship between the index of $filearray2 (i.e. $j) and the index of the info you're trying to get in $filearray.

Diego

[lorddraco98]

Originally posted by diego25
That info is in the first array that you've created with file(), right? And, if you look at the indeces, you can probably find a relationship between the index of $filearray2 (i.e. $j) and the index of the info you're trying to get in $filearray.

Diego

yeah, that info is taken from the file()

i'm a little confused by what you mean with looking over the indicies. could you explain more if possible?

[diego25]

In $result1, Artist 4 has an index of 3, right? The filename (artist4.mp3) which is in $filearray has an index of 7. So, to get from 3 to 7, you can multiply 3 by 2 and add 1. Check for the other artists - you'll see that the math formula works for them too.

Diego

[lorddraco98]

hrm, i'll give that a try, btw diego, do you have AIM or MSN? I'd like to to talk you via IM sometime, i have some more questions 😉

[diego25]

Well, I do have msn (canada_diego_at_hotmail.com) but I'm rarely online though...

Besides, I'd recommend you post your questions in this board. This way, if I'm not available for some reason, other people can answer your question. And other people who might have a similar question can also benefit from your post.

Diego

[lorddraco98]

allright, thanks 🙂
Another question lol, sorry about this, this is a tough script for me :/
here's what I have. Problem is, $updatedm3u2 isn't showing the 2 lines it should. For the 1st line it's showing aritst3-title3 which shouldn't be there cause that was in the $deletedsongs array
any ideas what I'm doing wrong?

<?php
//start process m3u function
function prunem3u($deletesongs, $filepath)
{
@$fp= fopen($filepath, "a+");
if (!$fp)
{
echo "Couldn't open file";
exit;
}
@$filearray= file($filepath);
if (!$filearray)
{
echo "couldn't get file";
exit;
}
$result= array_diff($filearray, $deletesongs);
$arraynum= count($filearray);
$j=0;
//this is the array with the 1st line only from the m3u file
for ($i=0; $i<=$arraynum; $i+=2)
{
$filearray2[$j]= trim($filearray[$i]); 
$j++;
}
$arraynum2= count($filearray2);
for ($i=0; $i<=$arraynum2; $i++)
{
echo $filearray2[$i]."<br>";
}
//this is the artist-title separated out from filearray2
for ($i=0; $i<=$arraynum2; $i++)
{
$filearray3[$i] = substr($filearray2[$i], strpos($filearray2[$i], ',')+1); 
echo $filearray3[$i]."<br>";
}
$result1= array_diff($filearray3, $deletesongs);
print_r($result1);
echo "<br>"; 
$arraynum3= count($result1);
$arraynum4= count($deletesongs);
for ($i=0; $i<=$arraynum4; $i++)
{
echo $deletesongs[$i]."<br>";
}
$k = 0;
$a=0;
foreach ($result1 as $key => $value)
{
if (($j=array_search($value, $filearray3)))
{
$updatedm3u[$k]= $filearray2[$j];
$num1[$a]=$k;
$k++;
$a++;
}
}
$arraynum5= count($updatedm3u);
for ($i=0; $i<=$arraynum5; $i++)
{
echo $updatedm3u[$i]."<br>";
}
echo "done<br>";
$m=0;
$n=1;
$p=1;
foreach ($updatedm3u as $key => $value)
{
if ($z= array_search($value, $filearray3))
{
echo $z."<br>";
echo $m."<br>";
$num3= ($z*2)-1;
$num2= ($filearray[$p]*2)+1;
$updatedm3u2[$m]= $filearray[$num3];
$updatedm3u2[$n]= $filearray[$num2];
$m+2;
$n+2;
$p++;
}
}
$t= count($updatedm3u2);
for ($i=0; $i<=$t; $i++)
{
echo $updatedm3u2[$i]."<br>";
}
}

and this code got kinda complicated for me so it wouldn't surprise me if I screwed up somehow heh