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Notes }
The 0th character is H
The 1th character is e

The 2th character is l
The 3th character is l

The 4th character is o
5.4 Cleaning Strings

Often, the strings we get from files or users need to be cleaned up before we can use them. Two
common problems with raw data are the presence of extraneous whitespace, and incorrect
capitalization (uppercase versus lowercase).
5.4.1 Removing Whitespace

You can remove leading or trailing whitespace with the trim ( ), ltrim( ), and rtrim( ) functions:
$trimmed = trim(string [, charlist ]); $trimmed = ltrim(string [, charlist ]); $trimmed = rtrim(string
[, charlist ]);
trim( ) returns a copy of string with whitespace removed from the beginning and the end. ltrim( )
(the l is for left) does the same, but removes whitespace only from the start of the string. rtrim( ) (the
r is for right) removes whitespace only from the end of the string. The optional charlistargument is
a string that specifies all the characters to strip. The default characters to strip are given in Table 5.3.

Table 5.3: Default Characters Removed by trim( ), ltrim( ), and rtrim( )

Character ASCII value Meaning
“ “ 0x20 Space
“\t” 0x09 Tab
“\n” 0x0A Newline (line feed)
“\r” 0x0D Carriage return
“\0” 0x00 NUL-byte
“\x0B” 0x0B Vertical tab

Example:

$title = “ Programming PHP \n”; $str_1 = ltrim($title); // $str_1 is “Programming PHP \n” $str_2
= rtrim($title); // $str_2 is “ Programming PHP” $str_3 = trim($title); // $str_3 is “Programming
PHP”
Given a line of tab-separated data, use the charset argument to remove leading or trailing
whitespace without deleting the tabs:
$record = “ Pradip\tKumar\t35\tRiya \n”; $record = trim($record, “ \r\n\0\x0B”; // $record
is “Pradip\tKumar\t35\tRiya”
5.4.2 Changing Case

PHP has several functions for changing the case of strings: strtolower( ) and strtoupper( ) operate
on entire strings, ucfirst( ) operates only on the first character of the string, and ucwords( ) operates
on the first character of each word in the string. Each function takes a string to operate on as an
argument and returns a copy of that string, appropriately changed. For example:

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