`Count` chars

Suppose we want to find the most common letter in a string. We could do this with the built-in count_chars function in PHP.

When we pass this function a string, it returns an array of frequencies. Each letter is indexed as the key, and each count of instances is the value.

Example

The count_chars function can be used in a variety of ways. We can access indexes directly, or use a foreach loop to iterate and test.

Step 1 To begin we use a string that has 2 letter "A" chars, 3 lowercase "b" chars and some other values.

Step 2 We invoke the count_chars function and pass the string literal we just described to it.

Step 3 We can access the counts of characters directly with indexes. We use ord() to get an int from a char to use here.

Step 4 If a char was not found in the string, its count value is equal to 0. The question mark was not found.

Step 5 It is possible to iterate with a foreach-loop over the count array. If a value was not zero, we print it with echo.

// Step 1: use this string.
$test = "AAbbbcccc.";

// Step 2: call count chars.
$counts = count_chars($test);

// Step 3: print some counts that exist.
echo $counts[ord('A')], "\n";
echo $counts[ord('b')], "\n";
echo $counts[ord('c')], "\n";

// Step 4: if a value does not exist, it is empty.
echo $counts[ord('?')], "\n";

// Step 5: loop over all elements in the returned array.
//         Print the ones that have 1 or more count.
foreach ($counts as $key => $value) {
    if ($value != 0) {
        echo "Key exists: " . chr($key) . " = " . $value . "\n";
    }
}2
3
4
0
Key exists: . = 1
Key exists: A = 2
Key exists: b = 3
Key exists: c = 4

Some programming tasks in PHP are done with a custom function and for-loops. But with a built-in function like count_chars, we can sometimes reduce code and make programs simpler.

Count chars

Example

`Count` chars