Variable Hashes (Associated Array), which means we can set the keys. (Or values in children, France is a message) to the Array by using the following format.
The announced value variables Array (announced in the variable value to A Ray Hashes symbol % is used) such as.
%day_in_month = ( "January" => 31, "Febuary" => 29, "March" => 31);
%number_hashes = ( "01" => "Monday", "02 '=>" Tuesday "," 03 "=>" Wednesday ");
To access the value of a variable Array Hashes this form below.
print $day_in_month ( "January"); # 31 display.
print $number_hashes ( "01"); # display Monday.
Change the value of Array key need. Look like.
$day_in_month ( "Febuary") = 28; # %day_in_month = ( "January" => 31, "Febuary" => 28, "March" => 31);
To count all members of A-ray. (Array variables using the same simple).
print $#day_in_month; # value is 3.
To see all of Array key variables.
print key %day_in_month; # display January, Febuary, March.
@keys_day = keys %day_in_month; # keys can also collect an Array of Hashes in the Array variables with a simple consequence @keys_day = ( "January", "Febuary", "March").
ถ้าต้องการเรียกดูค่าทั้งหมดของตัวแปร Array แบบ Hashes
print values %day_in_month; # display 31, 28, 31.
Hash in Perl.
Array in Perl.
Array variable that refers to a simple variable array, which costs around other children in France it will be a number starting from 0, 1, 2, ... to becoming the variables in the Perl language A simple array. This model is used as follows.
The announced value variables Array (announced in the variable value to array Standard. Using the @symbol) such as.
@number_practice = (1, 2, 3, 4, 5);
@string_practice = ( "default", "with", "language", "Perl");
To access this Array variables are used as models.
print $number_practice[3]; # program will display 4.
print $string_practice[3]; # program to display Perl.
Changes in values in the children Array Alliance needed. Use the form below.
$number_practice[3] = 10; # therefore variable. @number_practice = (1, 2, 3, 10, 5).
$string_practice[3] = "C"; # therefore variable. @string_practice = ( "start," with "," language "," C ").
To determine the number of members of the Array using the following form.
print $#number_practice; # 5 displayed.
The need to reduce the number of members of the Array using the following form.
$#number_practice = 3; # means that the lower member of the array to the remaining 3.
To view all the values of variables a simple Array.
print @number_practice; # Display 1 2 3 10 5.
print @string_practice; # display default language to C.
Scalar variable in Perl.
Scalar variables are common variables that can be either numeric character string, such as time.
$ a = "8"; # $ a variable is a string value "8".
$ b = 5; # variable $ b is a numeric value 5.
$ c = $ a 5; # remove string variables. (Plus symbol) to figure it will be immediately converted to numbers. Therefore, in this case would have cost $ c variable is 13.
$ d = $ a. "1"; # remove string variables. (symbol dot) with any number or string. Up to a string value. Therefore, in this case, the variable $ d to have a "81".
Using "until" and "do..until" for looping.
- "until" is looping statement for condition is false. Value opposite while.
$a = 0;
until ($a <0) (
print $ a. ",";
$a--;
)
# 0 will be displayed, because when set to $a = 0 then the check is if the conditions $a <0 to undo the block command. So if $a = 0 is a blog command until the display value from the variable $a after that $a will be reduced up to 1 value, so $a = -1 and the Blue of the year to check conditions again. Will be real terms. When conditions are true. Is the cross-block command in a command Lou year to another.
- do ... until the check until the conditions are similar to the instructions on the blog when conditions are false. And it will work like the do ... while in the first round to take command in a do ... until then check conditions before.
$ a = -1;
do (.
print $ a. ",";
$ a -;
) Until ($ a <0);
# Values are expressed -1, 0.
Using "while" and "do..while" statement.
- "while" is statement for looping same "for" statment. It has format follow.
$a = 0;
while ($a <3) (
$a;
print $a. ",";
)
# Values are shown 1, 2, 3 due to 0 $ a start when loop while on the condition that if $ a is less than 3 in order to make the blog. Over conditions. Will provide variable $ a (Added 1 value) Therefore, when this variable $ a = 1 then display output. Then to check the conditions while until conditions are false.
- do ... while a function like while (condition) () command, but do .. while the first block in order to do do .. while before gradually to check conditions into account, such as when finishing.
$a = 3;
do (
print $ a. ",";
$a--;
) While ($a <3);
# When viewing the variable $ a is 3 and will be valuable in terms of checks in order while the check that if $ a <3 to do in order blog. But in this case, a command do ... while when set to variable $ a = 3 will be made on the blog do ... while the command immediately without prior conditions examined. When a command in the block and then erase the value $ a to a variable cost, so now at $ a = 2, then in order to check conditions while on the set. But in this case, the year of the endless Blue (overflow) to describe, but easy to understand. This command has raised the issue.
Using for statement
- for (;;;) are used as models. (If the language used through PHP, C or some other language, the language may be familiar with this syntax).
for ($i = 1; $i <10; $i++) (
)
# $i mean set to start as 1 and checks that $i is not less than 10 or if less than 10, follow the instructions on the blog. When instructions complete in block (in each round) is the variable $i++ (the plus to add 1) and then check the conditions.
- using "for" statement for display value of all member in array.
for $value (@array) (
print $value;
)
- Displaying keys in member of array.
for $i (keys %array) (
print $i;
)
# For displaying value of all member in array by using keys reference.
for $i (keys %array) (
print $array ($i);
)
Using If and unless statement
Sentence review the terms of the Perl language instructions check the following conditions.
- If that distinction is out.
- Command if ().
if ($ number == 1) (.
).
if ($ string eq "welcome") (.
).
- Command if () else ().
if ($ number == 1) (.
) Else (.
).
- Command if () elsif ().
if ($ number == 1) (.
) Elsif ($ number == 2) (.
).
- Command if () elsif () else ().
if ($ number == 1) (.
) Elsif ($ number == 2) (.
) Else (.
).
- Unless the audit condition is another concern. Used in the opposite if (or other words meaning equal concern else).
unless ($ number == 1) (.
).
# This means that if the variable $ number is not equal to 1.
Join member of array into string
Array of integration into a string. A member of array is included into a string. The separator can be set as needed.
join ( 'separator you want', array).
Eg.
@ a = ( "Hello,", "Welcome", "Perl! \ n");
$ a = join ( '', @ a);
# Is included in all array separated by '' (space 1 box), hence $ a = "Hello, Welcome Perl! \ N".
$ b = join ( 'and', @ a);
# $ B = "Hello, and Welcome and Perl! \ N".
$ c = join ('', @ a);
# $ C = "Hello, WelcomePerl! \ N".
Split word in string
Split words (Split String) is divided by a string of variables required to store the Pattern string to break into the A-ray.
split (/ character to break a word /, variables like divided, the number you want).
Eg.
$ a = "Hello, Welcome Perl \ n";
@ a = split (/ /, $ a);
# Find a divide words when spaces 1 box (/ /) Therefore, @ a = ( "Hello,", "Welcome", "Perl \ n").
@ a = split (/ /, $ a, 2);
# Find a divide words when spaces 1 box (/ /) The amount to only 2 Therefore, the @ a = ( "Hello,", "Welcome").
Replace word in string
Replace the word is used in conjunction with a cut that is cut out words in the desired location. Then replace the string you want.
substr (string variable, as the starting cut, the number you want) = "string you want to go instead."
Eg.
$ a = "Welcome to Java! \ n";
substr ($ a, 11, 4) = "Perl";
# This means that the cut out words from position 11 to number 4 is out there to replace the word Java and Perl enter Therefore $ a = "Welcome to Perl! \ N".
substr ($ a, 7, 3) = "";
# This means that the cut out words from position 7 to 3 the number is out there "to" and replace with the word "go hence $ a =" Welcome Perl! \ N ".
substr ($ a, 0, 0) = "Hello,";
# This means that the cut out words from position 0 to 0 a That is not cut out any words out. Then replace the string "Hello," Therefore $ a = "Hello, Welcome Perl! \ N".
Substring in Perl
Substring is Wrapping is selected from the string as desired. Use the form below.
substr (variables like Wrapping, starting position, the number you want. If not entered, it took out after the start position);
Eg.
$ a = "Welcome to Perl! \ n;
print substr ($ a, 0, 7);
# Display "Welcome".
print substr ($ a, 7);
Display # "to Perl! \ N".
print substr ($ a, -6, 4);
# Display "Perl" (-6 means that much from his last position 6).
Introduction Perl language
Language Perl stands for Practical Extraction and Report Language that was developed by Mr. Larry Wall harbor in 1986 to be used with UNIX operating systems (Unix), especially when that is developed. applications on UNIX operating system is complex and requires knowledge of the language programs in languages such as working with files that need to grep or awk language and change language files with sed.
But the current language perl compatible with multiple operating systems such as UNIX, Linux, MVS, VMS, MS / DOS, Macintosh, OS / 2, Amiga and other languages and because Perl is the ability to manage files, text. very well made Perl language become important language is used on another Internet network.