Technical Interview Question #1

interview_question_1.php

<?php

function sum_csv($str,$sep,$col) {
	return floatval(array_reduce(array_slice(explode("\n",$str),1),
		function ($a,$l) use ($col,$sep) {
			return $a + explode($sep,$l)[$col];
		}));
}


$table = [
	'0.0' => "",
	'1.5' => "col1,col2\n0.0,0.5\n,1,1",
	'3.8' => "col1,col2,\n0.1,0.2\n0,0.6\n0,1\n0,2.0",
];

foreach ( $table as $t=>$str ) {
	if ( floatval($t) != sum_csv($str,",",1)) {
		die("Failed\n");
	} else {
		echo "$t passed with " . sum_csv($str,",",1) . "\n";
	}
}
echo "All functional tests passed\n";

function sum_csv_iter($str,$sep,$col) {
	$sum = 0;
	foreach ( array_slice( explode("\n",$str), 1) as $line ) {
		$cols = explode($sep,$line);
		$sum += $cols[$col];
	}
	return $sum;
}
foreach ( $table as $t=>$str ) {
	if ( floatval($t) != sum_csv_iter($str,",",1)) {
		die("Failed\n");
	} else {
		echo "$t passed with " . sum_csv_iter($str,",",1) . "\n";
	}
}
echo "All iterative tests passed\n";