count rows of a file with same first character - php

Question

In a comma separated csv file, I want to count the number of rows only where the the first number is same.
Following is the example data, I want to get number of rows which start with 2 (2 rows), and the rows which start with 4 (3 rows). This is just an example, the numbers are random.:
2,0,0
2,1,0
4,0,0
4,3,0
4,4,0
I'm trying following code, I can count only all rows of the file but do not know how can I count only the rows which have same first number.
$i = 0;
while ($i < 5) { //fixed number of times
$i++;
$rows = 0;
$fp = fopen("test.csv", "r");
while (fgetcsv($fp)) { //don't want all rows
$rows++;
}
fclose($fp);
echo $rows;
}
Edit:
Sorry, I forgot to mention the numbers in above file are random, they are not always 2 or 4.

Answer 1

You will need an array to get statistics.
$i = 0;
$agg = []; // to count stats
while ($i < 5) {
$i++;
$rows = 0;
$fp = fopen("test.csv", "r");
while ($line = fgetcsv($fp)) {
$number = $line[0]; // get first number
if(isset($agg[$number])){ // if there is the number in stats
$agg[$number]++; // count new one
} else {
$agg[$number] = 1; // mark as found one
}
}
fclose($fp);
print_r($agg);
}

Answer 2

You could probably try something like this :
$i = 0;
while ($i < 5) { //fixed number of times
$i++;
$rows = array();
$fp = fopen("test.csv", "r");
while ($data = fgetcsv($fp)) {
$first = $data[0];
if(isset($rows[$first]) {
$rows[$first] += 1;
} else {
$rows[$first] = 1;
}
}
fclose($fp);
print_r($rows);
}
I didn't test my code, so it may contains errors.
After the execution, $rows will contain an associative array with the form 'first number' => 'count'
What I don't understand however is why you are doing it five times and also why you are not using a for loop for that instead of a while ?

Answer 3

Assuming you know how to get the contents of the text file, something like this should work:
$ar = explode("\n",$txtfileContents);
$counts = array();
foreach($ar as $row){
$counts[$row[0]]++;
}
$counts now contains an array of all first characters and how many times they appeared. You can now simply access them like this:
echo "'2' appeared ".$count['2']." times<br/>";
echo "'4' appeared ".$count['4']." times";
Step by step:
Split the text file into an array of individual rows:
$ar = explode("\n",$txtfileContents);
(Try alternatively file() here, which may be more reliable than explode)
Loop through it:
foreach($ar as $row){
}
Then check the first character inside the loop and count each character separately:
$counts[$row[0]]++;