Finding duplicate column values in a CSV

Question

I'm importing a CSV that has 3 columns, one of these columns could have duplicate records.

I have 2 things to check:

1. The field 'NAME' is not null and is a string
2. The field 'ID' is unique

So far, I'm parsing the CSV file, once and checking that 1. (NAME is valid), which if it fails, it simply breaks out of the while loop and stops.

I guess the question is, how I'd check that ID is unique?

I have fields like the following:

NAME,  ID,
Bob,   1,
Tom,   2,
James, 1,
Terry, 3,
Joe,   4,

This would output something like `Duplicate ID on line 3'

Thanks

P.S this CSV file has more columns and can have around 100,000 records. I have simplified it for a specific reason to solve the duplicate column/field

Thanks

Answer 1

Give it a try:

    $row = 1;
    $totalIDs = array();
    if (($handle = fopen('/tmp/test1.csv', "r")) !== FALSE) 
    {
        while (($data = fgetcsv($handle)) !== FALSE) 
        {                           
            $name = '';
            
            if (isset($data[0]) && $data[0] != '')
            {
                $name = $data[0];
                if (is_numeric($data[0]) || !is_string($data[0]))
                    echo "Name is not a string for row $row\n";
            }
            else
            {
                echo "Name not set for row $row\n";     
            }
            
            $id = '';
            if (isset($data[1]))
            {
                $id = $data[1];                 
            }
            else
            {
                echo "ID not set for row $row\n";               
            }
            
            if (isset($totalIDs[$id])) {
                echo "Duplicate ID on line $row\n";
            }
            else {
                $totalIDs[$id] = 1;
            }
        
            $row++;
        }
        fclose($handle);
    }

Answer 2

<?php
$cnt = 0;
$arr=array();
if (($handle = fopen("1.csv", "r")) !== FALSE) {
    while (($data = fgetcsv($handle, 1000, ",")) !== FALSE) {
         $num=count($data);
         $cnt++;
         for ($c=0; $c < $num; $c++) {
           if(is_numeric($data[$c])){
                if (array_key_exists($data[$c], $arr)) 
                    $arrdup[] = "duplicate value at ".($cnt-1); 
                else
                    $arr[$data[$c]] = $data[$c-1];
            }   
        }
    }
    fclose($handle);
}
print_r($arrdup);