Scala String: Creating String, Concatenation, String Length

1. Scala String – Objective

In this chapter, we will discuss Scala String in Detail. After this, you will be able to create a string in Scala. Moreover, we will learn how to create a format string and concatenate strings in Scala.

So, let’s start the Scala String Tutorial.

Introduction to Scala String

Introduction to Scala String

2. Introduction to Strings in Scala

An immutable object, a string in Scala is a sequence of characters. Once we declare it, we cannot modify it. The following is a Scala string:

3. Creating a Scala String

To define a string, we can use a ‘var’ or a ‘val’. When we use ‘var’, we can reassign to it. This isn’t the same with ‘val’:

scala> var word="rest"
word: String = rest
scala> word="reset"
word: String = reset

By the way, reassigning ‘word’ to an Int will cause an error:

scala> word=7
<console>:12: error: type mismatch;
found   : Int(7)
required: String

Now with ‘val’:

scala> val word="rest"
word: String = rest
scala> word="reset"
<console>:12: error: reassignment to val

We can also mention the data type if we don’t want to rely on type inference.

scala> var word:String="rest"
word: String = rest
scala> word="reset"
word: String = reset

To make a lot of changes in your Scala string, you can use the StringBuilder class instead.

4. Find Length of a Scala String

An accessor method is one that’ll tell us about an object. One such method for strings is length(). It returns the number of characters a string holds. In the previous example,

scala> word.length()
res0: Int = 5

Here are more than a couple more examples:

scala> "Ayushi".length()
res1: Int = 6
scala> "".length()
res2: Int = 0
scala> " ".length()
res3: Int = 1

5. Concatenating Scala Strings

Concatenating two strings in Scala means joining the second to the end of the first. For this, we have the method concat() in the String class:

scala> "ab".concat("cde")
res5: String = abcde

Let’s try using more than one:

scala> "Ayushi".concat(" ".concat("Sharma"))
res6: String = Ayushi Sharma

We could also have done this using the + operator:

scala> "Ayushi"+" "+"Sharma"
res7: String = Ayushi Sharma
Scala Quiz

6. Creating Format Strings in Scala

For the times we want to format numbers/values into our string, we can make use of one of the methods printf() and format(). Other than this, the class String has the method format() to return a String object instead of a PrintStream object.

scala> var (a:Int,b:Int,c:Int)=(7,8,9)
a: Int = 7
b: Int = 8
c: Int = 9
scala> printf("a=%d, b=%d, c=%d",a,b,c)

a=7, b=8, c=9
For Integer data, we used %d. For Float and String data, we use %f and %s, respectively.

7. Conclusion

Hence, we studied how to create Scala String and creating format string in Scala. Along with this, we learned to concatenate and find a length of string. Still, have a confusion, feel free to ask in the comment session.


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