The strtolower() function

This function returns the lowercase version of a given string.

Syntax: strtolower(string);

Example input:

$str1=" MY PROGRAM";
echo strtolower($str1);
echo "
";
echo $str1;

Example output:

my program

MY PROGRAM

The chunk_split() function

This function split a string into smaller strings.

Syntax: chunk_split(string,length,seperator);

length – the number of characters each smaller strings should contain.
seperator – this character will be inserted after every smaller string.

Example inputs:

$str1="A simple PHP Program";
echo chunk_split($str1,2,"@");

The ltrim() function

ltrim() removes whitespace and certain pre-defined characters from the left end of the string.

Example inputs:

$str1=" A simple PHP Program";
echo $str1;
echo "
";
echo ltrim($str1);

trim() function

The trim() function could be used to remove certain pre-defined characters from both ends of a string.
Syntax: trim(string, [list of characters]);
string- the string in which the predefined characters are to be removed.
list of characters.
\0 for NULL
\t for TAB
\n for new line
“ ” for whitespace
If the list of characters are not specified, all pre-defined characters would be removed.

Example inputs

1.
$first_name = “James ”;
echo $first_name.”
”;
trim($first_name);
echo first_name;
In the output, the second echo function prints $first_name that has one less space.

2.
$name = “John
”;
echo $name.”
”;
trim($name);
echo $name;
In this case, the second time $name is printed, the new line character is absent.