Looping through an array an not extracting any duplicates...

[mkosmosports]

Hey,

IS there a way to run a loop on an array and echo only unique entries. Below is my array which contains several duplicates.

$transferyear[] = substr($row["DATE_FORMAT(START_DATE,'%Y%m')"],0,4);

Now Id like to run a loop and echo the unique values in that array.

Help appreciated.
Thanks!

[trq]

[code]
<?php
  $duplicate_array = array("foo","bar","boo","foo","bar");
  $clean_array = array_unique($duplicate_array);
  foreach($clean_array as $arr) {
    echo $arr."\n";
  }
?>
[/code]

[mkosmosports]

Damn, I was so close thorpe. Thats almost what I had but not quite. Thanks for your help once again!

[obsidian]

Out of curiosity, is there a reason you can't query for DISTINCT from the database and avoid the hassle of having to parse it in your PHP script?

[mkosmosports]

Well, initially thats what Im doing:
$alltransferdates = @mysql_query("SELECT DISTINCT DATE_FORMAT(START_DATE,'%Y%m') FROM sf_team_player");

Then:

while($row = mysql_fetch_assoc($alltransferdates))
{
$transferdate[] = $row["DATE_FORMAT(START_DATE,'%Y%m')"];
$transferyear[] = substr($row["DATE_FORMAT(START_DATE,'%Y%m')"],0,4);
}

I need to have the full date in an array hence $transferdate[].
Then Im dropping the %Y values into a separate array $transferyear[] because I also need to extract all the unique year values later on, and I couldnt figure out another way to do it.

[obsidian]

Well, I think thorpe may have the best idea, then, but let me suggest this to you as an alternative: try selecting the month and year separately and combining them into your first array, then inserting only the year into the second, if it's not already there:
[code]
<?php
$q = "SELECT DISTINCT DATE_FORMAT(START_DATE,'%Y%m') AS date, YEAR(START_DATE) AS year FROM sf_team_player";
$sql = mysql_query($q);
for ($i = 0; $i < mysql_num_rows($sql); $i++) {
  $date = mysql_result($sql, $i, 'date');
  $year = mysql_result($sql, $i, 'year');
  $transferdate[] = $date;
  if (!in_array($year, $transferyear)) $transferyear[] = $year;
}
?>
[/code]

You end up with the same results, but it's just a different approach. Hope this helps!

[mkosmosports]

Thanks Obsidian. I appreciate the time youve taken to suggest this method to me.

Ive tried the code you suggested originally and I get a php error on this line though:

if (!in_array($year, $transferyear)) $transferyear[] = $year; php is saying $transferyear is an undefined variable, I assume because its used before the array is defined? (I have global variables turned off, wonder if that could be why)

Then I thought you made a type, since shouldnt it check if $year exists in the $transferdate array:

  if (!in_array($year, $transferdate)) $transferyear[] = $year;

But that cant be it, because the $transfer year array no longer contains unique year values, it contains all of them.

I guess its the global variables then. You think?

[obsidian]

No, I think that all you need to do is declare your empty variables outside of the loop:
[code]
<?php
$q = "SELECT DISTINCT DATE_FORMAT(START_DATE,'%Y%m') AS date, YEAR(START_DATE) AS year FROM sf_team_player";
$sql = mysql_query($q);
$transferdate = array();
$transferyear = array();
for ($i = 0; $i < mysql_num_rows($sql); $i++) {
  $date = mysql_result($sql, $i, 'date');
  $year = mysql_result($sql, $i, 'year');
  $transferdate[] = $date;
  if (!in_array($year, $transferyear)) $transferyear[] = $year;
}
?>
[/code]

Also, what the code is doing is [b]only[/b] adding the $year to the $transferyear array if it does not already exist in there. That's how it makes it a unique listing.

[mkosmosports]

Youre the man obsidian. And dont worry, soon I wont be asking about what I asked about in my last post...lol. Soon Ill be figuring those out. I should of figured it out this time around.

Your method is better for me because there is one more situation Id like to cover with it, and I have a gut feeling it will be easier.
The reason I need to know all of the unique years is because there is a page where Id like to give the user links to all available data in the years that I have covered in by db. Now, there is one more thing though. Those urls containing the unique year dates also contain month parameters. I want to find a way I can get the max month from each unique year value. So,
$q = "SELECT DISTINCT DATE_FORMAT(START_DATE,'%Y%m') AS date, YEAR(START_DATE) AS year FROM sf_team_player WHERE OLDCLUB_ID IS NOT NULL ORDER BY START_DATE DESC";
$alltransferdates = mysql_query($q);
$transferyear = array();
for ($i = 0; $i < mysql_num_rows($alltransferdates); $i++)
{
  $date = mysql_result($alltransferdates, $i, 'date');
  $year = mysql_result($alltransferdates, $i, 'year');
  $transferdate[] = $date;
  if (!in_array($year, $transferyear)) $transferyear[] = $year;
}

Then on the page where I want the dynamic links I have a loop which returns the number of unique years in the form of links.

foreach ($transferyear as $tryear)
{
echo("<a href=\"players.html?view=transfers&season=$tryear&in=$in\">$tryear</a>");
}

Now though, Id like to replace the $in parameter with the max month for that unique year.

Now, Ive tried some things, but Ive had no success. Im thinking I need to make $transferyear a multidimensional array containing also the max month for each year, but I cant get it together. Any ideas?

Thanks!

[mkosmosports]

Bumping it up in case obsidian pops up again. Obsidian, youre not gonna leave me hanging at the last hurdle.... :D

[obsidian]

OK, I'll try not to leave you haning ;) ... Since you're already ordering by date DESC, you know that the first record you come across (the one from which you are populating your [b]year[/b] array) is going to have the latest date for that year. With that in mind, just modify your query to return the month as well, and you can have both together:
[code]
<?php
$q = "SELECT DISTINCT DATE_FORMAT(START_DATE,'%Y%m') AS date, YEAR(START_DATE) AS year, MONTH(START_DATE) AS month FROM sf_team_player WHERE OLDCLUB_ID IS NOT NULL ORDER BY START_DATE DESC";
$alltransferdates = mysql_query($q);
$transferyear = array();
$maxmonth = array();
for ($i = 0; $i < mysql_num_rows($alltransferdates); $i++) {
  $date  = mysql_result($alltransferdates, $i, 'date');
  $year  = mysql_result($alltransferdates, $i, 'year');
  $month = mysql_result($alltransferdates, $i, 'month');
  $transferdate[] = $date;
  if (!in_array($year, $transferyear)) {
    $transferyear[] = $year;
    $maxmonth[] = $month
  }
}
?>
[/code]

Then, once you have the two arrays, you can loop through them together and associate the year to the max month:
[code]
<?php
foreach ($transferyear as $key => $val) {
  $month = $maxmonth[$key];
  echo "$month is the max month for the year $val<br />\n";
}
?>
[/code]

Does this help some?