s is the string you want to perform the substr operation on i is the first character that you want to extract n is the last character you want to match
So if you said substr( "hello", 2, 4 ) it would match the second, third and fourth character and return ell.
Let me explain the code I gave
In the above example, the first argument to substr is $0 (which in this case is the text piped to it - "$0" is the entire record). The second argument is 0 (I could also have used 1) because I want to match from the start of the string. I want to grab the first four characters, so the third argument is 4.
The above code also makes use length(string) command to return the number of characters in the string.
So here, I'm saying "return the substring from the first character (which is the length of the string minus 3), up until the very end of the string".
To clarify this:
So in our substr, we grab from character 4 to character 7 inclusive, which are chars 4,5,6,7 - the last 4 chars.
how to parse the command line argument to look for '@' sign and the following with '.'.
In my shell script one of the argument passed is email address. I want to parse this email address to look for correct format.
rmjoe123@hotmail.com has '@' sign and followed by a '.'
to be more... (1 Reply)
Hi,
I have a requirement. I have an application which can take a file as inputs. Now the file can contain any number of lines. The tool has to pick up the first uncommented line and begin processing it.
For example the file could be like this:
#MANI123|MANI1234
#MANI234|MANI247... (4 Replies)
I have record line somthing like below with first line showing char spacing not real record line
1 | 2 | 3rd Field--------------|-4th field--| This is charcatersapcing of line
DF20000000000000000130.7890000000750
I shoudl get two line from above line
1st line should
1 | 2 | 3rd... (3 Replies)
#I'm quite new to scripting and my boss has asked me to solve a simple problem and sadly, I can't figure out how to do it. Any help is appreciated.
:confused:
#The following is a small shell script and the output that it produces for google.com.
#!/bin/sh
whois $1 | grep "Name Server"... (5 Replies)
Hey guys,
I have this file generated by me... i want to create some HTML output from it.
The problem is that i am really confused about how do I go about reading the file.
The file is in the following format:
TID1 Name1 ATime=xx AResult=yyy AExpected=yyy BTime=xx BResult=yyy... (8 Replies)
Hi everybody, I have a string stored in a variable called record:
record="SNMPv2-SMI::ent.9.9.43.1.3.9.2 = Timeticks: (177330898) 20 days, 12:35:08.98"
I want to write some regular expressions good for Korn Shell to extract the number between parenthesis, in this case 177330898, and put it in... (3 Replies)
I have a xml file like this
<bul:collectionStrategy name="strategy1">
<bul:collectionTemplateGroup name="15min group"/>
<bul:collectionTemplateGroup name="hourly group"/>
</bul:collectionStrategy>
<bul:CollectionTemplateGroup name="hourly group" >
... (2 Replies)
I have a file parameters.txt which contains
151524
151525
I have another file OID.csv which contains
NE Version Object Type ID SDK param name Object OID
test1 Start: 4.2 End: 4.2 pan 151524 speed ... (5 Replies)
Well, issue is i have to parse this script to get the VERSION:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>CFBundleAllowMixedLocalizations</key>
... (9 Replies)
Hi,
I need some guidance with understanding this Perl script below. I am not the author of the script and the author has not leave any documentation. I supposed it is meant to be 'easy' if you're a Perl or regex guru. I am having problem understanding what regex to use :confused: The script does... (3 Replies)
Discussion started by: newbie_01
3 Replies
LEARN ABOUT PHP
substr
SUBSTR(3) 1 SUBSTR(3)substr - Return part of a stringSYNOPSIS
string substr (string $string, int $start, [int $length])
DESCRIPTION
Returns the portion of $string specified by the $start and $length parameters.
PARAMETERS
o $string
- The input string. Must be one character or longer.
o $start
- If $start is non-negative, the returned string will start at the $start'th position in $string, counting from zero. For
instance, in the string ' abcdef', the character at position 0 is ' a', the character at position 2 is ' c', and so forth. If
$start is negative, the returned string will start at the $start'th character from the end of $string. If $string is less than or
equal to $start characters long, FALSE will be returned.
Example #1
Using a negative $start
<?php
$rest = substr("abcdef", -1); // returns "f"
$rest = substr("abcdef", -2); // returns "ef"
$rest = substr("abcdef", -3, 1); // returns "d"
?>
o $length
- If $length is given and is positive, the string returned will contain at most $length characters beginning from $start (depend-
ing on the length of $string). If $length is given and is negative, then that many characters will be omitted from the end of
$string (after the start position has been calculated when a $start is negative). If $start denotes the position of this trunca-
tion or beyond, false will be returned. If $length is given and is 0, FALSE or NULL, an empty string will be returned. If
$length is omitted, the substring starting from $start until the end of the string will be returned.
Example #2
Using a negative $length
<?php
$rest = substr("abcdef", 0, -1); // returns "abcde"
$rest = substr("abcdef", 2, -1); // returns "cde"
$rest = substr("abcdef", 4, -4); // returns false
$rest = substr("abcdef", -3, -1); // returns "de"
?>
RETURN VALUES
Returns the extracted part of $string; or FALSE on failure, or an empty string.
CHANGELOG
+--------------+---------------------------------------------------+
| Version | |
| | |
| | Description |
| | |
+--------------+---------------------------------------------------+
|5.2.2 - 5.2.6 | |
| | |
| | If the $start parameter indicates the position |
| | of a negative truncation or beyond, false is |
| | returned. Other versions get the string from |
| | start. |
| | |
+--------------+---------------------------------------------------+
EXAMPLES
Example #3
Basic substr(3) usage
<?php
echo substr('abcdef', 1); // bcdef
echo substr('abcdef', 1, 3); // bcd
echo substr('abcdef', 0, 4); // abcd
echo substr('abcdef', 0, 8); // abcdef
echo substr('abcdef', -1, 1); // f
// Accessing single characters in a string
// can also be achieved using "square brackets"
$string = 'abcdef';
echo $string[0]; // a
echo $string[3]; // d
echo $string[strlen($string)-1]; // f
?>
Example #4
substr(3) casting behaviour
<?php
class apple {
public function __toString() {
return "green";
}
}
echo "1) ".var_export(substr("pear", 0, 2), true).PHP_EOL;
echo "2) ".var_export(substr(54321, 0, 2), true).PHP_EOL;
echo "3) ".var_export(substr(new apple(), 0, 2), true).PHP_EOL;
echo "4) ".var_export(substr(true, 0, 1), true).PHP_EOL;
echo "5) ".var_export(substr(false, 0, 1), true).PHP_EOL;
echo "6) ".var_export(substr("", 0, 1), true).PHP_EOL;
echo "7) ".var_export(substr(1.2e3, 0, 4), true).PHP_EOL;
?>
The above example will output:
1) 'pe'
2) '54'
3) 'gr'
4) '1'
5) false
6) false
7) '1200'
ERRORS /EXCEPTIONS
Returns FALSE on error.
Example #5
<?php
var_dump(substr('a', 1)); // bool(false)
?>
SEE ALSO strrchr(3), substr_replace(3), preg_match(3), trim(3), mb_substr(3), wordwrap(3), String access and modification by character.
PHP Documentation Group SUBSTR(3)