Page 118 - Open Soource Technologies 304.indd

Web Technologies-I

Notes For example, to build a crude horizontal rule:
echo str_repeat(‘-’, 40);
The str_pad( ) function pads one string with another. Optionally, you can say what string to pad
with, and whether to pad on the left, right, or both:
$padded = str_pad(to_pad, length [, with [, pad_type ]]);

The default is to pad on the right with spaces:
$string = str_pad(‘Pradip Kumar’, 30); echo “$string:35:Riya”; Pradip Kumar :35:Riya
The optional third argument is the string to pad with:

$string = str_pad(‘Pradip Kumar’, 30, ‘. ‘); echo “{$string}35”; Pradip Kumar. . . . . . . .35
The optional fourth argument can be either STR_PAD_RIGHT (the default), STR_PAD_LEFT, or
STR_PAD_BOTH (to centre). For example:
echo ‘[‘ . str_pad(‘Pradip Kumar’, 30, ‘ ‘, STR_PAD_LEFT) . “]\n”; echo ‘[‘ . str_pad(‘Pradip Kumar’,
30, ‘ ‘, STR_PAD_BOTH) . “]\n”; [ Pradip Kumar] [ Pradip Kumar ]

5.7.3 Decomposing a String
PHP provides several functions to let you break a string into smaller components. In increasing
order of complexity, they are explode( ), strtok( ), and sscanf( ).
Exploding and Imploding
Data often arrives as strings, which must be broken down into an array of values. For instance,
you might want to separate out the comma-separated fields from a string such as”Pradip,25,Riya”.
In these situations, use the explode( ) function:
$array = explode(separator, string [, limit]);
The first argument, separator, is a string containing the field separator. The second argument,
string, is the string to split. The optional third argument, limit, is the maximum number of values
to return in the array. If the limit is reached, the last element of the array contains the remainder
of the string:
$input = ‘Pradip, 25, Riya’; $fields = explode (‘,’, $input); // $fields is array (‘Pradip’, ‘25’, ‘Riya’)
$fields = explode (‘,’, $input, 2); // $fields is array (‘Pradip’, ‘25, Riya’)
The implode ( ) function does the exact opposite of explode ( )—it creates a large string from an
array of smaller strings:
$string = implode (separator, array);
The first argument, separator, is the string to put between the elements of the second argument,
array. To reconstruct the simple comma-separated value string, simply say:
$fields = array(‘Pradip’, ‘25’, ‘Riya’); $string = implode(‘,’, $fields); // $string is ‘Pradip,25,Riya’

The join( ) function is an alias for implode( ).
Tokenizing
The strtok( ) function lets you iterate through a string, getting a new chunk (token) each time.
The first time you call it, you need to pass two arguments: the string to iterate over and the token
separator:
$first_chunk = strtok(string, separator);

112 LOVELY PROFESSIONAL UNIVERSITY