Find and Replace a Column in CSV1 based on CSV2 in PHP - php

Question

I am trying replace the values of column "Close" in the first CSV with the values of column "LTP" in the second CSV where the following columns should be same in CSV2 and CSV1:
"Symbol=SYMBOL", "Date=TIMESTAMP", "Expiry=EXPIRY_DT", "Option Type=OPTION_TYP", "Strike Price=STRIKE_PR"
Here is the current structure of CSV1:
INSTRUMENT SYMBOL EXPIRY_DT STRIKE_PR OPTION_TYP OPEN HIGH LOW CLOSE SETTLE_PR CONTRACTS VAL_INLAKH OPEN_INT CHG_IN_OI TIMESTAMP
OPTSTK INFY 26-Apr-18 780 CE 0 0 0 408.6 361.05 0 0 0 0 2-Apr-18
OPTSTK INFY 26-Apr-18 800 CE 0 0 0 388.95 341.15 0 0 0 0 2-Apr-18
OPTSTK INFY 26-Apr-18 820 CE 0 0 0 369.35 321.25 0 0 0 0 2-Apr-18
OPTSTK INFY 26-Apr-18 840 CE 0 0 0 349.75 301.35 0 0 0 0 2-Apr-18
OPTSTK INFY 26-Apr-18 860 CE 0 0 0 330.2 281.45 0 0 0 0 2-Apr-18
OPTSTK INFY 26-Apr-18 880 CE 0 0 0 310.75 261.55 0 0 0 0 2-Apr-18
OPTSTK INFY 26-Apr-18 900 CE 0 0 0 291.35 241.65 0 0 0 0 2-Apr-18
OPTSTK INFY 26-Apr-18 920 CE 0 0 0 272.15 221.75 0 0 0 0 2-Apr-18
OPTSTK INFY 26-Apr-18 940 CE 0 0 0 216 201.85 0 0 5400 0 2-Apr-18
OPTSTK INFY 26-Apr-18 960 CE 0 0 0 234.45 181.95 0 0 0 0 2-Apr-18
OPTSTK INFY 26-Apr-18 980 CE 0 0 0 216.1 162.1 0 0 0 0 2-Apr-18
OPTSTK INFY 26-Apr-18 1000 CE 0 0 0 136 142.3 0 0 24600 0 2-Apr-18
And the structure of CSV2 is:
Symbol Date Expiry Option Type Strike Price Open High Low Close LTP Settle Price No. of contracts Turnover in Lacs Premium Turnover in Lacs Open Int Change in OI Underlying Value
INFY 2-Apr-18 26-Apr-18 CE 780 0 0 0 408.6 0 361.05 0 0 0 0 0 1137.15
INFY 2-Apr-18 26-Apr-18 CE 1380 1 1 1 1 1 1 1 8.29 0.01 600 600 1137.15
INFY 2-Apr-18 26-Apr-18 CE 820 0 0 0 369.35 0 321.25 0 0 0 0 0 1137.15
INFY 2-Apr-18 26-Apr-18 CE 840 0 0 0 349.75 0 301.35 0 0 0 0 0 1137.15
INFY 2-Apr-18 26-Apr-18 CE 860 0 0 0 330.2 0 281.45 0 0 0 0 0 1137.15
INFY 2-Apr-18 26-Apr-18 CE 880 0 0 0 310.75 0 261.55 0 0 0 0 0 1137.15
INFY 2-Apr-18 26-Apr-18 CE 900 0 0 0 291.35 0 241.65 0 0 0 0 0 1137.15
INFY 2-Apr-18 26-Apr-18 CE 920 0 0 0 272.15 0 221.75 0 0 0 0 0 1137.15
INFY 2-Apr-18 26-Apr-18 CE 940 0 0 0 216 216 201.85 0 0 0 5400 0 1137.15
INFY 2-Apr-18 26-Apr-18 CE 960 0 0 0 234.45 0 181.95 0 0 0 0 0 1137.15
INFY 2-Apr-18 26-Apr-18 CE 980 0 0 0 216.1 0 162.1 0 0 0 0 0 1137.15
INFY 2-Apr-18 26-Apr-18 CE 1000 0 0 0 136 134 142.3 0 0 0 24600 0 1137.15
INFY 2-Apr-18 26-Apr-18 CE 1020 0 0 0 126 126 122.65 0 0 0 1200 0 1137.15

Answer 1

A few things about CSV and in general any file
I am trying replace the values of column "Close" in the first CSV with the values of column "LTP" in the second CSV where the following columns.
You cannot "replace" anything in the file. You can however pull the data from a file using fgetcsv then change it and write a new file with the changed data using fputcsv.
As you have shown "no code", I won't bother writing much. But I will just go over the process.
read in the file (completely) with the new values in it, creating an array from it
read in the file you wish to change row by row
for each row of the second file, find the correct row in the first one (array) and update the data for that line in file #2 (your file #1)
write a new file that contains the updated data.
you have to read the file you want to change the data in last, because you want to preserve the order of the rows in that file, and well it's just easier that way.
A tip for matching the data. When you read in file #1 take the fields you need to match and hash them using md5. Md5 is really fast on the order of something like 5 million hashes a second (yes I timed it)
$time = microtime(true);
for($i=0; $i <= 5000000; ++$i){
md5("hello world");
}
echo "Complete :".number_format((microtime(true) - $time), 4);
Try it yourself
Output
Complete :1.3057
Now this has nothing to do with security or anything else, I will explain in a second.
When you build you array (Step 1) take the fields you want to match and hash them and use that for the key in your array.
$hash = md5(
$row['Symbol'] .
strtotime($row['Date']) . //convert to timestamp
$row['Expiry'] .
$row['Option Typ'] .
$row['Strike Price']
);
$data[$hash] = $row;
Then do the same when you read in the second file (the file you want to modify)
$newHash = md5(
$row['SYMBOL'] .
TIMESTAMP . //convert to timestamp
$row['EXPIRY_DT'] .
$row['OPTION_TYP'] .
$row['STRIKE_PR'] .
);
Then simply look up the hash in the $data array isset($data[$newHash]) as yo go through the file you are modifying. Once you find the row with that data you need the rest is pretty trivial.
Now the basic way to read a file is
$h = fopen('filename.csv', 'r');
$data = [];
$headers = false;
while(!feof($h)){
$row = fgetcsv($h);
if(!$headers) $headers = $row;
$row = array_combine($headers, $row);
//do the hash "and other stuff"
$data[$hash] = $row;
}
Then read the other file after that one is done, with the same kind of loop, do the hash , match the data you want, update the old data, write the row in a new (3rd) file etc...
For the hashing to work, the data must match from one CSV to the other (obviously), there cannot be duplicate "hashed" rows. Rows who's data hashes the same but which has values in the other fields. Like if you had 2 rows in the same file that hash the same and then the Close value is different. This would cause you trouble no matter what.
Good luck, look up some tutorials on how to process CSV files, there are plenty of them out there.