Python programming language provides the following types of loops to handle looping requirements. Python provides three ways for executing the loops. While all the ways provide similar basic functionality, they differ in their syntax and condition checking time.
A for loop is used for iterating over a sequence (that is either a list, a tuple, a dictionary, a set, or a string).
This is less like the for keyword in other programming languages, and works more like an iterator method as found in other object-orientated programming languages.
With the for loop we can execute a set of statements, once for each item in a list, tuple, set etc.
fruits = ["apple", "banana", "cherry"]
for x in fruits:
print(x)
The for loop does not require an indexing variable to set beforehand.
Even strings are iterable objects, they contain a sequence of characters:
fruits = ["apple", "banana", "cherry"]
for x in fruits:
if x == "banana":
break
print(x)
With the continue statement we can stop the current iteration of the loop, and continue with the next:
fruits = ["apple", "banana", "cherry"]
for x in fruits:
if x == "banana":
continue
print(x)
To loop through a set of code a specified number of times, we can use the range() function,
The range() function returns a sequence of numbers, starting from 0 by default, and increments by 1 (by default), and ends at a specified number.
for x in range(7):
print(x)
Note that range(6) is not the values of 0 to 6, but the values 0 to 6.
The range() function defaults to 0 as a starting value, however it is possible to specify the starting value by adding a parameter: range(2, 6), which means values from 2 to 6 (but not including 6):
for x in range(2, 6):
print(x)
The range() function defaults to increment the sequence by 1, however, it is possible to specify the increment value by adding a third parameter: range(2, 30, 3):
for x in range(2, 30, 3):
print(x)
The else
keyword in a for
loop specifies a block of code to be executed when the loop is finished:
for x in range(6):
print(x)
else:
print("Finally finished!")
Note: The else
block will NOT be executed if the loop is stopped by a break
statement.
A nested loop is a loop inside a loop.
The “inner loop” will be executed one time for each iteration of the “outer loop”:
adj = ["red", "big", "tasty"]
fruits = ["apple", "banana", "cherry"]
for x in adj:
for y in fruits:
print(x, y)
The while loop in Python is used to iterate over a block of code as long as the test expression (condition) is true.
We generally use this loop when we don’t know the number of times to iterate beforehand.
while expression: Body
Let’s see it with an example
i=0
while i < 5:
print(i)
i=i+1
Here, the loop will run until the condition gets false and it will exit the loop.
#Output
0
1
2
3
4
Same as with for loops, while loops can also have an optional else
block.
The else
part is executed if the condition in the while loop evaluates to False
.
The while loop can be terminated with a break statement. In such cases, the else
part is ignored. Hence, a while loop’s else
part runs if no break occurs and the condition is false.
Here is an example to illustrate this
counter = 0
while counter < 3:
print("Inside loop")
counter = counter + 1
else:
print("Inside else")
Output
Inside loop
Inside loop
Inside loop
Inside else
Here, we use a counter variable to print the string Inside loop three times.
On the fourth iteration, the condition in while
becomes False
. Hence, the else
part is executed.
Conclusion
Hence we studied different types of loops in python with there definition and implementation along with it.
This brings the end of this Blog. We really appreciate your time.
Hope you liked it.
Do visit our page www.zigya.com/blog for more informative blogs on Data Science
Keep Reading! Cheers!
Zigya Academy
BEING RELEVANT
Through the standard form offers different advantages in mathematical calculations and scientific notation. Firstly, it…
Introduction Stress is a feeling caused by an external trigger that makes us frustrated, such…
Sociology is a broad discipline that examines societal issues. It looks at the meaningful patterns…
Some info about Inch Inches are a unique measure that persuades us that even the…
You should be familiar with logarithms to understand antilogarithms in a better manner. Logarithms involve…
यहां "नाटककार सुरेंद्र वर्मा" पुस्तक की पीडीएफ विद्यार्थी, शोधार्थी और जो इसका अभ्यास के लिए…