The **`ctype_lower` method**  checks if all the text characters are in lowercase alphabetical characters.

> The lowercase alphabetical characters include `a-z`.

#   
#  Syntax

```
ctype_lower(mixed $text): bool
```

This method returns a Boolean value.

##  
## Code

<?php 

  $str = "abc";
  printIsLower($str);

  $str = "aaaaa";
  printIsLower($str);

  $str = "A";
  printIsLower($str);

  $str = "123abc";
  printIsLower($str);

  function printIsLower($str){
    echo "The string is: ". $str. "\n";
    echo "Is Lower: ";
    var_dump(ctype_lower($str));
    echo "---------\n";
  }

?>

#   
#  Explanation

In the code above: 

* We used the `ctype_lower` method to check if the string contains only lowercase alphabetical characters. 

* For the string `abc` and `aaaa`, the `ctype_lower` method returns `true`.

* But for the string `A` and `123abc`, the `ctype_lower` method returns `false` because the string contains the uppercase letter `A` and numeric characters, respectively.
---

##   
## Things to note
If an int value ranging from -128 to 128 is passed as an argument, it is internally converted as an ASCII character. Then it is checked if the converted character is a numeric character. See the example below.

<?php 
    var_dump(ctype_lower(97)); // 97 is equivalent to charcter `a` in ASCII
?>


In the code above, we passed `97` as an argument. First, it is internally converted as ASCII character `a` and then checked if it is a lowercase alphabetical character. `a` is a lowercase character, so `true` is returned.

What is the ctype_lower method in PHP?

The ctype_lower method checks if all characters in a string are lowercase a-z, returning a Boolean value.