Swift while loop
The while loop in Swift works the same as it does in other programming languages. It is used to keep running a target statement as long as a condition is actual. When the state is false, the loop will terminate, and the line following the loop will execute. This loop executes a series of statements until it encounters a faulty condition. This loop is commonly used when the number of iterations is unknown.
Syntax:
while (TestExpression)
{
// statements
}
In this case, TestExpression is a Boolean expression. If it is true,
- The while loop executes the statements inside it.
- The TestExpression is then evaluated once more.
This continues until the test expression returns false. The while loop ends when the TestExpression encounters the faulty condition.
Flowchart of While loop
Example:
var j = 3
// Iterate the while loop till j<50
While j < 6{
print("Coding Ninjas Studio")
j = j + 1
}
Output:
Coding Ninjas Studio
Coding Ninjas Studio
Coding Ninjas Studio
The while loop is executed in the preceding program until the condition is evaluated as false, and it quits as soon as it receives the false condition.
Swift for-in loop
The for-in loop in Swift is used to repeat a piece of code a specific number of times. It can iterate through any sequence, including an array, a range, a string, etc.
Syntax:
for index in var
{
// statement
}
Flowchart of a for-in loop
Example 1: Loop Over Array
let lang = ["C", "C++", "Swift", "JavaScript"]
for l in lang {
print(l)
}
Output:
C
C++
Swift
Javascript
We built an array called lang in the previous example.
The value of l is first set to the first element of the array, Swift, which produce the print statement inside the loop to be run.
The print statement is called again when the l has been updated with the next element of the array. The loop will continue until the array's last segment is accessed.
Example 2: for loop with where Clause
With a for-in loop in Swift, we can easily include a where Clause. It's used in the loop to implement filters. The loop will execute if the condition where Clause returns true.
// remove C from an array
let lang = ["C", "C++", "Java", "Python"]
for lan in lang where lan != "C"{
print(lang)
}
Output:
C++
Java
Python
The code written inside the loop will run if the condition inside where Clause returns true. Otherwise, it will not be carried out.
Example 3: for loop With Range
A range is a collection of values that fall between two numerical intervals.
// iterate from i = 1 to 1 = 7
for i in 1...7 {
print(i)
}
Output:
1
2
3
4
5
6
7
The for-in loop was used to iterate over a range of 1 to 3 in the preceding example.
Example 4: for Loop with Stride Function
Instead of range, we must use the stride(from:to:by) function if we want a loop to increment by a fixed value in each iteration.
for j in stride(from: 1, to: 8, by: 2) {
print(j)
}
Output:
1
3
5
7
The loop iterates over the Range of 1 to 8 with an interval of 2 in the example above. The number 8 is not included in the series, though.
Swift repeat-while loop
The repeat-while loop is used in Swift to repeatedly execute a block of code or a series of statements. The repeat-while loop is very similar to the while loop with the exception that it will run the statements at least once even if the condition is FALSE because it will execute the body first and then check the state. In contrast, the while loop will only run the statements when the form is TRUE.
Syntax:
repeat
{
// statements
} while (condition)
The repeat-while loop in Swift is equivalent to the do-while loop in other programming languages.
Flow chart of repeat-while loop
Example:
var i = 1, n = 8
// repeat...while loop from 1 to 8
repeat {
print(i)
i = i + 1
} while (i <= n)
Output:
1
2
3
4
5
6
7
8
Frequently Asked Questions
Why are loops required?
Loops are computer constructs that repeat a code section until the desired process is completed. Loops are vital for saving time and minimizing errors in programming since repetitive operations are expected.
Is the do-while loop is same as the repeat-while in Swift?
Yes, both are the same. Both loop body guaranteed to execute at least once.
What is the most common problem with loops?
Another typical mistake when constructing loops is to create a loop that never ends. An infinite loop is what this is known as. If your program contains an endless loop, it may display the same output repeatedly.
What are the advantages of utilizing loops?
A loop is used in computer programming to run a set of instructions or a block of code several times without writing it again.
Conclusion
The concept of Swift loops has been thoroughly covered in this article. We began with an overview of Swift loops and then went over each loop form in detail, complete with explanations, code, and output statements.
We hope that this blog has improved your understanding of Swift loops. If you would like to learn more, check out our blogs, the Definitive Swift Tutorial for Beginners, why iOS & OS X Developers choose Swift? and which is better to learn? iOS or Android?.
Happy learning!
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