PHP count the number of occurances of values of a variable

Question

This has to do with counting in PHP, and there are numerous questions and examples of that, but none that I can find of what I need to do: count the occurrences of the value of a variable and output that count as its own variable.

The values I want to count and output as variables are each of the 50 state two letter abbreviations, i.e. AL, AK AR...; they are contained in $state.

What's the most efficient way to count the number of occurrences of each state and output each as a variable, i.e. $AL_total and $AK_total and $AR_total, etc.?

// I have data in the format
// firstname\n lastname \naddress \ncity \nstate \nzip
// This explode strings into array
foreach($values as $val) {
$valuearray = explode("\n", implode($val));

// This assigns variables that are used to echo each field of data
$firstname = $valuearray[0];
$lastname = $valuearray[1];
$address = $valuearray[2];
$city = $valuearray[3];
$state = $valuearray[4];
$zip = $valuearray[5];

// count $state and output as $AL_total , $AK_total , $AR_total , etc.


// And then...

echo $AL_total;

etc....

array_count_values() ?

mighty_dev
– mighty_dev

2021-12-15 19:07:51 +00:00
Commented Dec 15, 2021 at 19:07 — mighty_dev
– mighty_dev, Commented Dec 15, 2021 at 19:07
aha, I think that's what I need :)

BlueDogRanch
– BlueDogRanch

2021-12-15 19:19:46 +00:00
Commented Dec 15, 2021 at 19:19 — BlueDogRanch
– BlueDogRanch, Commented Dec 15, 2021 at 19:19

masterguru · Accepted Answer · 2021-12-15 21:13:30Z

1

This could be an aproach based in your initial requirements:

#inside the loop

$states[$state] = null;

if (!isset(${$state . '_total'})) {
    ${$state . '_total'} = 1;
} else {
    ${$state . '_total'} += 1;
}

And then:

#after the loop
foreach ($states as $state => $_null) {
    echo "Total ".$state." = ".${$state . '_total'}."\n";
}

And if you want to ouput a specific state that you know it:

#after the loop
echo "Total AL = ".((isset($AL_total)) ? $AL_total : 0);

You can see it runing here

And if you prefer to get a single array using array_count_values() function (as commented by @nice_dev) the do the following:

#inside the loop
$states_count[] = $state;

And then:

#after the loop
$count_by_state = array_count_values($states_count);
print_r($count_by_state);
echo "Total AL = ".(isset($count_by_state['AL']) ? $count_by_state['AL'] : 0);

will output something like this:

Array
(
    [AN] => 1
    [AK] => 5
    [AR] => 5
    [AL] => 4
)
Total AL = 4

You can see it running here

edited Dec 15, 2021 at 21:13

answered Dec 15, 2021 at 19:28

masterguru

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8 Comments

BlueDogRanch Over a year ago

Thanks, that's interesting and it works. nice_dev pointed out the possible use of array_count_values(). Would that be easier?

masterguru Over a year ago

@BlueDogRanch: It depends of how do you want to manage them. First I did it in the way you were asking for in your inital post. Now I have added the array_count_values() function that will generate an array with all values that you could access via $count_by_state[state] instead $state_total vars. As you wish. Surely the array_count_values() solution looks better and cleaner than the other.

BlueDogRanch Over a year ago

Thanks! Using array_count_values works better for me; the first example killed my loop for some reason. And it appears to be more efficient.

BlueDogRanch Over a year ago

Ah, Warning: Undefined array key "AL" when AL is 0, I guess. Do we need to check if a key exists when we echo "Total AL = ".$count_by_state['AL']; ?

masterguru Over a year ago

@BlueDogRanch: I have edited my answer and added the array verification. Also updated the link to test it again.

|

Alan · Accepted Answer · 2021-12-15 19:33:58Z

0

I would recommend using an associative array where the keys are the states and the values are the counts, e.g.:

# before your loop:
$stateCount = [];

# in your loop:
if( ! isset( $stateCount[$state] ) ) { # first time $state is seen, init to 1
    $stateCount[$state] = 1;
} else {
    $stateCount[$state]++;
}

edited Dec 15, 2021 at 19:33

answered Dec 15, 2021 at 19:08

Alan

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4 Comments

BlueDogRanch Over a year ago

nice_dev pointed out the possible use of array_count_values(). Would that be easier?

Alan Over a year ago

imo, your array for counting would be unnecessarily large (and use up more memory) with using array_count_values

BlueDogRanch Over a year ago

That's interesting. How do I output the total for i.e., AL? Is that echo $al?

Alan Over a year ago

I recommend reading up on how associative arrays work in PHP: php.net/manual/en/language.types.array.php. To access AL, you would use echo $stateCount['AL'];

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