php string part 3

Strings
TYBSc. Comp. Sci.
Chapter 2- Functions & Strings
monica deshmane(H.V.Desai college) 1

Points to learn
String
• Manipulating strings
• Decomposing string
• String searching functions
• Decomposing URLs

Manipulating String
• This function searches string or character in a
given string.
• It returns false if string or character is not
found.
• What we require?
• Str1
• Str2
• Syntax-
• $pos = strpos(large string, small string);
1. strpos()

Manipulating String
$str = "Welcome to PHP Programming, Here is the string";
$pos = strpos($str, “ing");
echo $pos;
pos = 23
strrpos() – This function finds the last occurance of character
in a string.
$pos = strrpos($str, “ing");
echo $pos;
pos = 43
1. strpos() $pos = strpos(large string, small string);

Manipulating String
2. substring
Function used To take part of string
What we require?
String
Start index
How much characters to retrieve
Syntax-
substr (string,start,no.of characters)

Manipulating String
2. substring substr (string,start,no.of characters)
$str1= "Welcome";
$str2 = substr($str1, 3);
$str3 = substr($str1, 2, 3);
echo "$str2 $str3";
Output: come lco

Manipulating String
3. Substring count
Function used To count how much times small
string present within large string.
What we require?
String(in what)
Small string
How much characters to retrieve
Syntax-
Substr_count (string,substring)

Manipulating String
3. Substring count Substr_count (string,substring)
$str = <<< my_doc
This is document writtern using heredoc.
This is used to display the multilines.
This is how it works. This ends here.
my_doc;
echo $str;
$cnt = substr_count($str, "is");
echo " Count is : $cnt";
This ends here.
Count is : 8

Manipulating String
4. Substring replacement
Function used To replace small/ sub string within large string.
What we require?
Large String(in what)
Small string
How much characters to replace
Syntax-
substr_replace($str, substring, start, no.of characters);

Manipulating String
4. Substring replacement
substr_replace($str, substring, start, no.of characters);
//replace the string
$str = "Welcome to HTML Programming";
$newstr = substr_replace($str, "PHP", 11, 4);
echo $newstr;
Welcome to PHP Programming
//insert without deleting
$newstr = substr_replace($newstr, "Core lang ", 15, 0);
echo " $newstr";
Welcome to HTML Core lang Programming
//replacement of "" without inserting
$newstr = substr_replace($newstr, "", 15, 5);
echo " $newstr";

Manipulating String
4. Substring replacement Continue…
//insert at the beginning of the srting
$newstr = substr_replace($newstr, "Hi ", 0, 0);
echo " $newstr";
//number of characters from the end of the string from which to start the
replacement
$newstr = substr_replace($newstr, "examples", -11);
echo " $newstr";
//deletes from start and keeps length characters
$newstr = substr_replace($newstr, "", -12, -8);
echo " $newstr";

Manipulating String
5. string replacement
Function used To replace 1 string with other string.
What we require?
Str1(what)
Str2(by what)
Str(in what)
How much characters to replace
Syntax-
Str_replace(what,by what,inwhat,[cnt])

Manipulating String
5. string replacement Str_replace(what,by what,inwhat,cnt)
$newstr = str_replace(“o”,”i”,$str);
echo $newstr;

Manipulating String
6. String reverse Strrev(string)
$newstr = strrev($str);
echo $newstr;

Manipulating String
7. String repeat Str_repeat(string,count)
echo str_repeat(“*”, 40);
Returns a new string consisting of string repeated number of times.

Manipulating String
8. String padding
Function used To pad characters in string.
What we require?
string
Total Length
Padding string
Position
Syntax-
str_pad(String, length, padding string,Position);
str_pad() pads one string with another. Bydefault it pads spaces on right hand side.
STR_PAD_LEFT – to pad on left side.
STR_PAD_BOTH – to pad on both the side.

Manipulating String
8. String padding
str_pad(String, length, padding string,Position);
$str = str_pad("Hello", 10);
echo " $str Student"; //Hello Student
$str = str_pad("Hello", 10, "*");
echo " $str Student"; //Hello***** Student
$str = str_pad("Hello", 10, "*", STR_PAD_LEFT);
echo " $str Student"; //*****Hello Student
$str = str_pad("Hello", 10, "*", STR_PAD_BOTH);
echo " $str Student“;//**Hello***Student

Revise manipulating string
1. $pos = strpos(large string, small string);
2. $str3 = substr($str1, 2, 3);
3. $cnt = substr_count($str, "This");
4. $newstr = substr_replace($str, "PHP", 11, 4);
5. $newstr = str_replace(“o”,”i”,$str,2);
6. $newstr = strrev($str);
7. echo str_repeat(“*”, 40);
8. $str = str_pad("Hello", 10, "*",
STR_PAD_LEFT);

strtok() – First time we need to pass two arguments.
To retrieve next tokens repeatedly call strtok() by passing one argument.
What we require?
String
Seperator
Syntax:-
$token = strtok($str, seperator);
Decomposing string
1. Tokenizing

$str = "C Programming, Dennis Richie, Wrox publication, 1000";
$token = strtok($str, ",");
while($token != false)
{
echo "$token ";
$token = strtok(",");
}
Output:
C Programming Dennis Richie Wrox publication 1000
Decomposing string
1. Tokenizing $token = strtok($str, seperator);

sscanf() – This function decomposes a string accoring to a printf(). This function returns
number of fields assigned.
What we require?
String
Scalar factors
Parameters to scan
Decomposing string
2. sscanf
Syntax-
sscanf($str, scalar factors, parameters)
Example-
$n = sscanf($str, "%st%s (%d)", $first, $last, $price);

sscanf() – This function decomposes a string accoring to a printf().
This function returns number of fields assigned.
$str = "CPPtTechMax (400)";
$n = sscanf($str, "%st%s (%d)", $first, $last, $MRP);
echo " Math Count : $n";
echo “Count = $n First = $first Second = $last price = $MRP";
Decomposing string
2. sscanf
sscanf($str, scalar factors, parameters)

monica deshmane(H.V.Desai college)
23
explode() - This function constructs array from string.
What we require?
seperator
String
Limit
Syntax-
$array = explode(separator, string[,limit]);
Decomposing string
3. Exploding and imploding-
explode()

24
$str = "C Programming, Dennis Richie, Wrox publication, 2000";
$arr = explode(",", $str);
print_r($arr);
Output:
Array ( [0] => C Programming [1] => Dennis Richie [2] => Wrox publication [3] => 2000)
•$str = "C Programming, Dennis Richie, Wrox publication, 1000";
$arr = explode(",", $str, 2);
print_r($arr);
Output:
Array ( [0] => C Programming [1] => Dennis Richie, Wrox publication, 1000 )
Decomposing string
explode()

25
implode() - This function constructs string from array.
This is reverse of explode().
Syntax-
$str = implode(separator, array);
$book = array("C Programming", "Dennis Richie", "Wrox publication", 5000);
$str = implode(",", $book);
echo " $str";
Decomposing string
implode() $str = implode(separator, array);

String searching functions
1.strpos()
$pos = strpos(large string, small string);
2. Strstr(string,substring)
1. strpos(seen previously)
2. strstr() or strchr() – This function searches for a given string into
original string. It returns the string starting from given string.
$str = "Welcome to PHP Programming, Here is the string";
$rem = strstr($str, "PHP");
echo " Remaining str : $rem";
Output: PHP Programming, Here is the string

3. stristr() 2. Stristr(string,substring)
This function is used to search string. This is case insensitive.
$rem = stristr($str, “php");
echo " Remaining str : $rem";
Output: PHP Programming, Here is the string

4.strspn() 5. strcspn()
4.strspn() – This function search for charset in beginning (1st word) of the
specified string. It returns the length depending upon number of characters
appeared from charset.
$length = strspn(string, charset);
$len = strspn("abcdefand",”bac");
Output: 3
$len = strspn(“programming in php",”phpin");
5. strcspn() - This function is reverse of strspn(). It tells you how much of the
start of the string is not composed of characters in character set.
$len = strcspn("abdnefbacnd","nt");
Output: 3

Revise string searching functions
1. $pos = strpos(large string, small string);
2. $rem = strstr($str, "PHP");
3. $rem = stristr($str, “php");
4. $len = strspn("abcdefand",”bac");
5. $len = strcspn("abdnefbacnd","nt");

Decomposing URLs
parse_url() parse_url(url)
This function returns array of components of a URL.
The possible keys of the hash are scheme, host, port, user, pass, path, query
and fragment.
$arr = parse_url("http://localhost:8080/onlineexam/test.html");
print_r($arr);
Output:
Array ( [scheme] => http [host] => localhost [port] => 8080 [path] =>
/onlineexam/test.html )

End of Presentation

php string part 3

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php string part 3