Perl Tutorial in PDF - Learn Perl in simple and easy steps starting from basic to advanced concepts with examples including Introduction, Environment, Syntax. Perl is a programming language developed by Larry Wall, especially designed for text processing in this tutorial, please notify us at [email protected] . Perl is a programming language developed by Larry Wall, especially designed for text processing. It stands for Download a quick Perl tutorial in PDF format.
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This tutorial will teach you basic Android programming and will also take you through some advance Advanced Andr Download Android Tutorial (PDF. Teach Yourself Perl 5 in 21 days. David Till. Table of Contents: Introduction q Who Should Read This Book? q Special Features of This Book q Programming. Many tutorials are available if you are interested in learning Perl. Please note that these tutorials are introductions. For reference material, please look at the perl.
We will be using some inbuilt Perl functions for doing this task. This is kind of dyn mic rr y The split function splits the content of string into an array based on the delimiter provided to it. This function will also eliminate the delimiter from the string, in this case, it is 'a'; Push, Pop, shift, unshift for Perl arrays: Perl Push: Perl Pop: Perl Shift: Perl Unshift: Let's see an example where we can use the below functions. Mon Tue Wed 2nd when push: Mon Tue Wed Thu 3rd when unshift: Fri Mon Tue Wed Thu 4th when pop: Fri Mon Tue Wed 5th when shift: We already learned about scalars and arrays in previous sections.
What exactly scalars do? It only stores integers and strings. What exactly arrays do? It is a collection of scalars, where you access each element of an array using indices. But, is this good idea to use an array when you have hundreds and thousands of records? We will forget which index has what value. To overcome this situation we have something like perl hash. What are Hashes?
A hash can also hold as many scalars as the array can hold. The only difference is we don't have any index rather we have keys and values.
Let's see an example how we can define a Perl hash and how we can differentiate this from array Consider an example of three people and their ages are represented in an array. Sainath33Krishna24Shruthi25 This way it is difficult to know individual ages as we need to remember both index locations of name and age of all the people.
It may be simple when you have 3 names, but when you have or more? You know the answer. This we can overcome using a hash. Hash Example: But, how do we access or print it? Each element in hash should be accessed with its associated key for which there will be a value assigned. So, there is a one-one mapping between each of the key and value in the hash. In order to print the age of any person, you just need to remember the name of that person.
Each Key in hash should be unique or else it will override your value, which was assigned previously. How can we assign a hash to another hash? Simple, same way as we do for We can also print entire hash. This is how we can do that. Delete is an inbuilt function of Perl. Here, we will see an example of assigning a hash to an array.
Whenever you print a hash or when you store hash into an array. The order may always differ. It's not the same always. We can assign only keys or values of a hash to an array. To remove all the entries in the hash, we can directly assign the hash to null. So, what are conditional statements? Conditional statements are those, where you actually check for some circumstances to be satisfied in your code.
Think about an example, you are downloading some fruits, and you don't like the price to be more than bucks. So, the rule here is bucks. Perl supports two types of conditional statements; they are if and unless. Perl If If code block will be executed, when the condition is true. Is it a limitation? No, you can also control various conditions using if… elsif … else. There could be situations where both if and elsif code blocks will be failed.
In this scenario, the else code block will be executed. You can actually eliminate the else code check if you don't like to include. Perl Nested If In this case, you can use if code block in one more if code block.
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Perl Unless You have already got an idea what if does If the condition is true it will execute the code block. Unless is opposite to if, unless code block will be executed if the condition is false. Inside 1st else block — The value is 5 Guess what will be the output. You are right!!!!!. The output will be the print statement of the else block.
Because of the condition in unless code block is true, remember unless block will be executed only if the condition is false.
Inside unless Block Perl Loops - Control Structures Perl supports control structures similar to other programming languages. Perl supports four types of control structures for, foreach, while and until. We use these statements to, repeatedly execute some code. For loop Perl For code block will execute till the condition is satisfied.
Let's take an example of how to Perl loop an array. The array index 0 value is 1 The array index 1 value is 2 The array index 2 value is 3 The array index 3 value is 4 The array index 4 value is 5 The array index 5 value is 6 The array index 6 value is 7 The array index 7 value is 8 The array index 8 value is 9 The array index 9 value is 10 Here, in for expression, there are many statements included.
There is a meaning for each of them. Let's take the same example with foreach perl. The value is 1 The value is 2 The value is 3 The value is 4 The value is 5 The value is 6 The value is 7 The value is 8 The value is 9 The value is 10 This looks good for accessing arrays. How about Hashes, how can we obtain hash keys and values using foreach?
We can use foreach to access keys and values of the hash by looping it. Keys is an inbuilt function of Perl where we can quickly access the keys of the hash. How about values? We can use values function for accessing values of the hash.
The code block will exit only if the condition is false. Let's take an example for Perl While loop. Here is a problem, which will require input from the user and will not exit until the number provided as '7'. Guess a Number Between 1 and 10 9 Guess a Number Between 1 and 10 5 Guess a Number Between 1 and 10 7 You guessed the lucky number 7 In the above example, the while condition will not be true if we enter input other than '7'.
If you see how while works here, the code block will execute only if the condition in a while is true. Perl do-while Do while loop will execute at least once even if the condition in the while section is false. Let's take the same example by using do while. Here, the code block will execute only if the condition in until block is false. Let's take the same example which we used in case of a while. Here is a problem, which will require input from the user and will not exit until the name provided as other than 'sai'.
Enter any name sai Perl do-until: Do until can be used only when we need a condition to be false, and it should be executed at-least once. Enter any name Howard Enter any name Sheldon Enter any name sai Execute while, do-while, until and do-until example codes to see the difference. Perl Operator What is Operator? Operators in computer language indicate an action that can be performed on some set of variables or values which computer can understand.
Perl has incorporated most of the Operators from C language. Perl has many operators compared with other programming languages. Operators are categorized as Arithmetic, Logical, relational and assignment operators. Arithmetic Operators: Arithmetic operators are those which can be used to perform some basic mathematic operations. These Arithmetic operators are binary operators where we need two arguments to perform a basic operation.
We can also use unary operators for other basic operations; you can see the difference in examples below. Add of 10 and 2 is 12 Sub of 10 and 2 is 8 Mul of 10 and 2 is 20 Div of 10 and 2 is 5 Exp of 10 and 2 is Mod of 10 and 2 is 0 Assignment Operators: Assignment operators simply assign values to variables, but there is one more thing which we need to remember here, assignment operators will also perform arithmetic operations and assign the new value to the same variable on which the operation is performed.
Perl uses logical operators to compare numbers and strings. Most of the time logical operators are used in Conditional Statements. True -- equal 5 and 5 True -- not equal 6 and 7 True -- 7 greater than 6 True -- 6 less than 7 True -- 6 less than 7 True -- 7 greater than 6 You can see examples of logical operators in later sections.
Special variables in Perl are those who have some predefined meaning. These variables denoted with either real Name or Punctuation symbols. We have a special variable for all the Perl supported Variables like scalar special variables, Array special variables, hash special variables. Most of the special variables that we use are of scalars. When we want to use the special variable with its name, then we have to load a Perl module 'use English,' to explicitly say Perl interpreter that we are going to use special variables using its Name.
By default value of this is set to 0, we can change the value of this variable. Holds the format of the currently selected output by default the file handle name. Status code: Pipe and system call. The return status of the command executed. Holds the values of the pattern matched in order. Array, a substring. In numeric context, prints the error number.
In string context, print the error. Warning switch. Array Special Variables: Variable Description INC Holds a list of paths, where Perl library modules or scripts can be looked into while executing the current script. This INC is used by use and require statements to look into those paths for library modules. ARGV Stores the command line arguments passed.
F This is the array into which the input lines are stored when auto split —a command line switch is used.
Hash Special Variables: Used by do, use and require. Perl regular expression is strong enough in matching the string patterns within a statements or group of statements. Regular expressions are mostly used in text parsing, pattern matching and much more based on the requirement. Match 0 or 1 character Can be used to match alternative patterns Used to store the pattern matched  Set of characters can be passed. Specifically used for numeric and alphabets. Let's see few examples. Consider a situation where user provides some input during script execution, and we want to check whether the user entered some name as input or not.
We have to write a regular expression syntax to extract your name and print the same. Let us see how exactly we can construct a Regex. Consider an example of a string of multiple words and digits and special symbols like this "Hello everyone this is my number: Perl Match Operators The match operators are used to match a string within some statement or in a variable.
The pattern can be anywhere in the variable. Perl Substitution Operator This operator can be used for searching and replacing any character with either null or some other character. We can actually use any pattern matching string as we did earlier in this substitution operator as well.
Here we used 'gi', g-globally, i-ignore case. Perl Translation Operator This is similar to Substitution, but it does not use any perl regular expressions, rather we can directly pass the value or a word which we want to replace. Perl main advantage is in file parsing and handling the files.
There are many inbuilt functions and operators used during file handling in Perl. In this tutorial, you will learn- Perl Open file We can open a file using open function available in Perl. Is it for reading or writing?
Consider we have a perl file with name file. We need to open this file and print the same. Now, we will write a program to create and write data to a perl file. The above way will always try to create a file named test. We will see few more examples and other functions which help in understanding more about files. This method is used to position the file pointer to a specific location by specifying the bytes followed by either start of the file pointer or end of the file pointer.
Zero will set it from the beginning of the file. Let input. We can also handle directories through which we can handle multiple files. We can use the opendir and readdir methods. Subroutines are similar to functions in other programming languages. We have already used some built-in functions like print, chomp, chop, etc. We can write our own subroutines in Perl.
These subroutines can be written anywhere in the program; it is preferable to place the subroutines either at the beginning or at the end of the code. Most of the reusable code requires parameters to be passed to the subroutine. Here, we will learn how we can pass arguments to the subroutine. Main functionality of subroutines is to do some task and return the result of the reusable code. We can return a value from subroutine using the return keyword.
We can also pass hashes and array directly to the subroutine. Inside Sub-routine2b1aAfter Sub-routine call2b1a Perl Format Perl has a mechanism using which we can generate reports.
Using this feature, we can make reports exactly the way we want while printing on the Output screen or in a file. A simple format can be written using printf or sprintf functions available in Perl. The same can be used for sprintf.
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Using printf and sprintf, we can obtain most of the Perl formats. In the case of reports, it will be difficult to implement. Example of a Report: This can be achieved by using the perl printf and perl sprintf.
It can effectively be implemented using format. A format can be declared in the below manner. Here, we will be using a particular method write to print the data onto output screen or into the file.
Assumes as a comment if single provided. Execute the code to see the output. We can change this to file handler which we are using to write data into the file. This will output the format to the file which we are working on.
Now wasn't it too simple and quick? You might be wondering why Perl is so famous on the Web. It is simple as most of the things that happen on the web are of TEXT and Perl is very good at text processing. If we compare Perl with any of the languages, then Perl will be the best language which is good in File handling, text processing, and output reporting One of the best advantages of Perl is that it is free to use The Perl community strongly believes that software should be freely available, freely modifiable and freely distributable.
Several volunteers from Perl community strive to make the programming language as good as possible. Pros: Cons: Compared to other Programming languages Perl is most powerful for text handling and Parsing This is an interpreted language with fast execution time as there is no need to compile a Perl script Simple and easy to program and understand. It is object oriented. CPAN library eases Perl development we will learn more about this later in the subject.
Used in Web development for mostly Payment Gateways. Used in Automation and to test most of the Network and Storage related stuff. There is minimal GUI support as compared to other Programming languages. You need to refer to complex library modules which are not so easy to understand Don't be scared once you know how to do the things everything will be easy.
Understanding complex Patterns requires experience. Let's get started With enough knowledge about the history of Perl and basic concepts of computer programming required for coding in Perl, it is time we take the dive and get started with Perl.
The next chapter will teach you how you can setup Perl on your system and get ready for the coding journey in Perl. The tutorial will take Linux as the OS which students will be using for coding in Perl. Good news you probably have it! But if you can't find it already on your system, you can still get it for free. To find out if you already have Perl installed, go into the command line and type: perl -v The command will display version of Perl if it's installed. In this case, the version is v5.
But if not… don't panic… Unix Already Installed Comes pre-installed with Perl though you may need to update to the latest version. The rest will be taken care of. Just make sure you have an active internet connection. Install perl for Windows: First, download the Active Perl from this link. Follow these steps to install ActivePerl on Windows system. See the below screenshots for the same.
Step 1: Once you download the installer and start the installation you will see the below window, click on next to proceed. Step 2: Accept Licensing agreement to proceed the installation. Step 3: Below are different packages that will be installed. By default, all will be selected. This is the utility provided by Active Perl to install external Perl modules or libraries in your system. Click on Next to proceed. Perl Regular expressions Perl split and join. Perl File handling Perl chop vs chomp.
Next Topic Perl Introduction. Verbal A. Compiler D. Web Tech. Cyber Sec. Control S.Operators are categorized as Arithmetic, Logical, relational and assignment operators.
This tutorial may contain inaccuracies or errors and tutorialspoint provides no guarantee regarding the accuracy of the site or its contents including this tutorial. That means that escaped characters and variables aren't simply literally inserted into later operations, but are evaluated on the spot.
Main functionality of subroutines is to do some task and return the result of the reusable code. True -- equal 5 and 5 True -- not equal 6 and 7 True -- 7 greater than 6 True -- 6 less than 7 True -- 6 less than 7 True -- 7 greater than 6 You can see examples of logical operators in later sections.