Perl Substring: How to Create and Use the Substring Function

perlstringfunctionsPerl programming has a lot of unique features that come with it. One of the special features of Perl is its functions. Functions are special properties of the programming language that you can utilize in order for you to manipulate a string in various ways.

If you’re interested in learning about Perl, then you will have to learn how to use the substring function along with various others. The best way to learn about programming languages such as Perl is to do some programming yourself. Check out the Udemy course, Beginning Perl so that you can get some firsthand experience in writing in this high-level language.

What is a Substring? 

In Perl, a substring is a special type of function. There are four parts of a substring function, which are called OFFSET, LENGTH, EXPR, and REPLACEMENT. Each of these parts can be used to manipulate a particular string.

For instance, OFFSET is where you want to begin the substring. The LENGTH is the number of characters you want the string to extend starting from the OFFSET. Remember that the OFFSET number.

As you can probably guess, the REPLACEMENT part of a substring allows you to replace the piece of the substring that you’ve created with something else.

If you really want to get the hang of learning how to use substrings, you should learn a lot about manipulating string functions. Strings are a key aspect of any programming language, and it’s not something that you can easily ignore. Learning about strings is easy though. Check out the Udemy course, Programming for Non-Programmers: Fundamentals, which teaches you all about the core concepts, such as strings.

Substring Examples

Although substrings can seem like it’s a complicated concept, there isn’t much to it. Below you will see a few examples of substrings and an explanation of how it works. This will show you how you can potentially use substrings in your own work and why they can be useful.

$newstring = substring(EXPR, OFFSET, LENGTH, REPLACEMENT):

Above is just the basic of what you’ve already been told. This is how a substring is structured. The $newstring is the result of what comes out of substring after you’re done manipulating it. The substring(EXPR, OFFSET, LENGTH, REPLACEMENT); part all indicate the four sections of the substring that you have to identify when you’re writing your substring. You should note that you don’t have to use the replacement part of the substring.

$string = “You can fit six people in the car.”;
$substring = substr($string, 10, 3);

Above is an example of a string where a substring has been identified. The string itself is “You can fit six people in the car.” It’s identified as a variable with $string.

The next line in the program $substring is the result of manipulating the original string. The substring identifies the tenth character in the string and it is extended for 3 characters. This is the OFFSET and the LENGTH. In this instance, the OFFSET is the letter s in the word six, and the LENGTH is three, which encompasses all of the letters in the word six.

If you were to print out the substring, it would now print six instead of the entire string. This is the piece of the string that the substring has been identified as, and now you can manipulate it and change it whatever you want.

This is only the first three parts of a substring. As mentioned before, you can also replace pieces of a string when you’re using the substring function. In order to do that you just have to add on a fourth parameter to the substring that was created before.

$substring = substr($string, 10, 3, ‘eleven’);

In this example, the #string expression is manipulated so that the word fix is changed with the word eleven. The 10th character, as mentioned before is the f in the string, and the following three characters all encompass the word fix. So when the new string is written out or $substring, it will read as follows.

You can fit eleven people in the car.

You can take different pieces or fragments from your string in any way you want, and you don’t have to use the LENGTH portion of the substring either. Here is an example that only utilizes the EXPR and OFFSET parts of the substring function.

$sentence = “This is the time for great men to stand up for what they believe in.”
$fragment = substring($sentence, 7);

What happens is if you were to print out the fragment it would read as follows:

The time for great men to stand up for what they believe in.

Since it is a fragment and it is offset by the 7th letter, which in this case is t, the sentence is cut off and starts from a new point. These are just a few examples of how you can use substrings in your programs. It is a very versatile function, and you can use it to solve a lot of problems in programming.

Exploring Programming More

If you’ve gotten the hang of Perl programming to the point that you feel comfortable doing things such as substrings, then you may be curious about other programming languages. There are many languages out there for you to choose from, and they can be very easy to learn. Once you’ve learned one programming language, the task of learning another can be done in a much shorter period of time.

For people that enjoy Perl programming, Python is usually another great language to learn. If you want to try your hand at Python, then you should check out the Udemy course The Ultimate Python Programming Tutorial.

This isn’t the only easy language you can learn though. Ruby is also famous for being an easy language to understand and use. You can also try your hand at this programming language by taking the Udemy course Ruby Programming for Beginners.