Refactoring PHP code - reducing number of foreach statements - php

Question

as you can see in my code below, I'm using the same code (foreach loop with array assignment and trailing json_decode) three times for three variables that are structured similarly. I'm wondering how I can optimize my code so that it doesn't repeat functions unnecessarily. Would variable variables be helpful in this situation? Can I move the recurring lines of code to inside the first foreach statement?
Here's what my code looks like now:
date_default_timezone_set('America/Los_Angeles');
$stocks = array('MSFT' => 'http://ichart.finance.yahoo.com/table.csv?s=MSFT', 'AAPL' => 'http://ichart.finance.yahoo.com/table.csv?s=AAPL', 'FB' => 'http://ichart.finance.yahoo.com/table.csv?s=FB', 'ZNGA' => 'http://ichart.finance.yahoo.com/table.csv?s=ZNGA');
foreach ($stocks as $key=>$stock) {
$fh = fopen($stock, 'r');
$header = fgetcsv($fh);
$varname = $key . '_data';
$$varname = array();
while ($line = fgetcsv($fh)) {
${$varname}[count($$varname)] = array_combine($header, $line);
}
fclose($fh);
}
foreach($MSFT_data as $val){
$MSFT[] = array((strtotime($val['Date']) * 1000), ((float)$val['Close']));
}
$MSFT = json_encode(array_reverse($MSFT));
foreach($AAPL_data as $val){
$AAPL[] = array((strtotime($val['Date']) * 1000), ((float)$val['Close']));
}
$AAPL = json_encode(array_reverse($AAPL));
foreach($FB_data as $val){
$FB[] = array((strtotime($val['Date']) * 1000), ((float)$val['Close']));
}
$FB = json_encode(array_reverse($FB));
Thanks. Let me know if you have any questions.

Answer 1

For the three loops, try:
function dateCloseLoop($data) {
foreach($data as $val){
$tmp[] = array((strtotime($val['Date']) * 1000), ((float)$val['Close']));
}
return json_encode(array_reverse($tmp));
}
So your code would be something like:
$MSFT = dateCloseLoop($MSFT_data);
$AAPL = dateCloseLoop($AAPL_data);
$FB = dateCloseLoop($FB_data);

Answer 2

You could just use an associative array, storing a data array for each stock key, and use nested foreach's on that nested array.
Something like this:
$res = array();
$stocks = array('MSFT' => '...', 'AAPL' => '...', 'FB' => '...', 'ZNGA' => '...');
foreach ($stocks as $stock => $url) {
$fh = fopen($url, 'r');
$header = fgetcsv($fh);
$res[$stock] = array();
while ($line = fgetcsv($fh)) {
$res[$stock][] = array_combine($header, $line);
}
fclose($fh);
}
$json = array();
foreach ($res as $stock => $data) {
$out = array();
foreach($data as $val){
$out[] = array((strtotime($val['Date']) * 1000), ((float)$val['Close']));
}
$json[$stock] = json_encode(array_reverse($out));
}