使用php在csv中进行计算

Question

First let me introduce myself: Im 33. 'Living in the Netherlands and i'm a newbe if it comes to php :)

I have a csv file on my vps httpdocs\data\1day.csv . In this file there are two columns: datetime and value. The file looks like this:

"datetime","value",
"2016-01-02 10:50:01","1060.9",
"2016-01-02 10:45:01","1060.6",

I want to make a simple calculation to the file 1day.csv and save it to another csv file. Let's say the caluclation will be value * 5:

"datetime","value","value2",
"2016-01-02 10:50:01","1060.9","5304.5",
"2016-01-02 10:45:01","1060.9","5304.5",

The calculation needs to be done over the whole "value" column.

I want to do this with php and let a cronjob execute this script every x minutes.

Can anybody help me in the right direction?

Answer 1

I would maybe do it more simple. If you didn't know how many columns you could do the extra loops to get column names, but it does not look necessary.

$output = "datetime, value1, value2
"; // Column names
while ($row = mysql_fetch_array($sql)) {
  $output .='"' . $row[0] . '" ,';
  $output .='"' . $row[1] . '" ,';
  $output .='"' . ($row[1] * 5) . '"';
  $output .="
";
}