[SOLVED] Calculating length of a streak

[ninedoors]

I have a sports website and I want to calculate the length of a team's streak whether it be a win, loss, or a tie.  So I retreive the array that has all of the teams outcomes and then reverse it.  This where I ran into the problem because I not sure what will work to get my desired result.  Here is what I tried:

<?php
$array = array("win", "win", "win", "tie", "win", "win", "tie", "loss", "tie", "win" );

$array1 = array_reverse($array);

$i = 1;

$outcome = $array1[0];

while ($outcome == $array1[$i])	
{
$i++;
}

if ($array1[0] > 1)	
{
echo "$i $array1[0] s";
}

else	
{ 
echo "$i $array1[0]"; 
}

?>

 

The array above is just the test array I am using to see if the code is working but it's not.  What I want is $streak =  3 wins, for this example array.  any help would be great.  Thanks

 

Nick

[Psycho]

I don't know why you would need to reverse it. A steak is the same whether it is goign forwards or backwards. Try this:

 

<?php

$winStreak = 0;
$lossStreak = 0;
$tieStreak = 0;
$tmpWin = 0;
$tmpLoss = 0;
$tmpTie = 0;

$outcomes = array("win", "win", "win", "tie", "win", "win", "tie", "loss", "tie", "win" );

foreach ($outcomes as $outcome) {

  switch ($outcome) {
    case 'win':
      $tmpWin++;
      $tmpLoss = 0;
      $tmpTie = 0;
      $winStreak = ($tmpWin>$winStreak)?$tmpWin:$winStreak;
      break;
    case 'loss':
      $tmpWin = 0;
      $tmpLoss++;
      $tmpTie = 0;
      $lossStreak = ($tmpLoss>$lossStreak)?$tmpLoss:$lossStreak;
      break;
    case 'tie':
      $tmpWin = 0;
      $tmpLoss = 0;
      $tmpTie++;
      $tieStreak = ($tmpTie>$tieStreak)?$tmpTie:$tieStreak;
      break;
}

?>

 

I'm sure there may be a more efficient solution, but this was the first to come to mind

[Fadion]

Its kinda the same approach as mjdamato's:

 

<?php
$outcomes = array("win", "win", "win", "tie", "win", "win", "tie", "loss", "tie", "win" );
$maxStreak = 0;
$streak = 0;
foreach($outcomes as $value){
if($value == 'win'){
	$streak++;
	if($streak > $maxStreak){
		$maxStreak = $streak;
	}
} else{
	$streak = 0;
}
}
echo $maxStreak;
?>

[Psycho]

Here, this is a little more compact - I love efficiency

 

<?php

$outcomes = array("win", "win", "win", "tie", "win", "win", "loss", "loss", "tie", "win" );

$outcome_types = array ('win', 'loss', 'tie');
foreach ($outcomes as $outcome) {

  foreach ($outcome_types as $type) {

    $tmp[$type] = ($outcome==$type)? $tmp[$type]+1 : 0 ;
    $streaks[$type] = ($tmp[$type]>$streaks[$type])? $tmp[$type] : $streaks[$type] ;
  }
}


//Output the results
foreach ($outcome_types as $type) {
  echo "The $type streak is: $streaks[$type]<br>";
}

// Output:
// The win streak is: 3
// The loss streak is: 2
// The tie streak is: 1

?>

[ninedoors]

GuiltyGear,

 

Your code works but it only finds the 'win' streaks.  I need to find any streak.  Meaning a streak of ties, losses or wins.

 

Nick

[hitman6003]

This will be faster with a larger number of items in the $outcomes array:

 

for ($i = 0; $i < count($outcomes); $i++) {
if (!$streaks[$outcomes[$i]]) {
	$streaks[$outcomes[$i]] = 1;
	$current_streak = 1;
}

if ($outcomes[$i] == $outcomes[$i + 1]) {
	$current_streak++;

	if ($current_streak > $streaks[$outcomes[$i]]) {
		$streaks[$outcomes[$i]]++;
	}
} else if ($outcomes[$i] != $outcomes[$i + 1]) {
	$current_streak = 1;
}
}

 

With 10 entries, they are about the same, with 100 entries the above is about 2.5 times faster.

 

<?php
$possible = array('win', 'tie', 'loss');

while (count($outcomes) <= 100) {
$outcomes[] = $possible[array_rand($possible)];
}

$start = microtime();

for ($i = 0; $i < count($outcomes); $i++) {
if (!$streaks[$outcomes[$i]]) {
	$streaks[$outcomes[$i]] = 1;
	$current_streak = 1;
}

if ($outcomes[$i] == $outcomes[$i + 1]) {
	$current_streak++;

	if ($current_streak > $streaks[$outcomes[$i]]) {
		$streaks[$outcomes[$i]]++;
	}
} else if ($outcomes[$i] != $outcomes[$i + 1]) {
	$current_streak = 1;
}
}

echo 'completion time for method: ' . (microtime() - $start) . ' seconds<br />Result:';
echo '<pre>' . print_r($streaks, true) . '</pre>';

$start = microtime();

$outcome_types = array ('win', 'loss', 'tie');
foreach ($outcomes as $outcome) {

  foreach ($outcome_types as $type) {

    $tmp[$type] = ($outcome==$type)? $tmp[$type]+1 : 0 ;
    $streaks[$type] = ($tmp[$type]>$streaks[$type])? $tmp[$type] : $streaks[$type] ;
  }
}

echo 'completion time for method: ' . (microtime() - $start) . ' seconds<br />Result:<br />';
foreach ($outcome_types as $type) {
  echo "The $type streak is: $streaks[$type]<br>";
}

//echo '<pre>' . print_r($outcomes, true);
?>

 

increasing the number of entries keeps the ratio about the same.

 

EDIT: I did test with a larger number of possibilities...6 to be exact: win, loss, tie, one, two, three.  This makes the time difference even larger: almost 5 times faster.  Although I don't know why you would have six possible results.....

[ninedoors]

I fixed it GuiltyGear.  Thanks, that works great.  Here's what I did incase you were wondering.

<?php
$outcomes = array("win", "win", "win", "tie", "loss", "tie", "win" );

$maxStreak = 0;
$streak = 0;

$a = $outcomes[0];

foreach($outcomes as $value){
if($value == $a){
	$streak++;
	if($streak > $maxStreak){
		$maxStreak = $streak;
	}
} else{
	$streak = 0;
}
}
echo $maxStreak;
?>

[Psycho]

Ok, I conceded that your process is faster than my 2nd attempt. But, I guess I should have been clearer on what "efficiency" I was after - which was efficiency in code, not necessarily speed.

 

Were only talking about thousands of a second difference. And, since you brought it up, my original code was about 2 - 3 times faster than the code you posted.

[Psycho]

I fixed it GuiltyGear.  Thanks, that works great.  Here's what I did incase you were wondering.

<?php
$outcomes = array("win", "win", "win", "tie", "loss", "tie", "win" );

$maxStreak = 0;
$streak = 0;

$a = $outcomes[0];

foreach($outcomes as $value){
if($value == $a){
	$streak++;
	if($streak > $maxStreak){
		$maxStreak = $streak;
	}
} else{
	$streak = 0;
}
}
echo $maxStreak;
?>

 

Do you realize that will only find the longest streak for the first outcome type in the array, not necessarily the longest streak?