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What is the difference between range() and xrange() in Python?
Key takeaways:
range():
The
range()function available in Python 3.It returns an immutable sequence object called a range object.
More memory-efficient and faster in Python 3.
Ideal for creating loops and performing repetitive tasks.
Efficiently handles large ranges (e.g.,
for i in range(1000000):). It uses an iterator, which saves memory compared to creating a full list.
xrange():
The
xrange()function available in Python 2.It returns a generator object that is memory-efficient for large sequences.
More memory-efficient for large ranges but slower in iteration.
Use
xrange()for large ranges in Python 2.
Let's take an example of building an app that processes 10 orders. You can use range() and xrange() in Python to loop through the order numbers automatically. This is easier and faster than writing the order numbers by hand. These functions help save time and memory when working with repetitive tasks.
range() function in Python
The range() function in Python creates a sequence of numbers. We can use it when we need to repeat something a specific number of times, like in a loop. In Python 3, range() returns a sequence object, not a list. This makes it more efficient.
Syntax of range() function
The syntax of range() is simple:
range(stop)range(start, stop)range(start, stop, step)
Parameters of the range() function
start: The number where the sequence starts (optional, defaults to 0).stop: The number where the sequence ends (required, but not included in the sequence).step: The amount to increase or decrease in each step (optional, defaults to 1).
Efficiency of range() function
In Python 3, range() is faster and more efficient than in Python 2 because it doesn’t create the entire list of numbers in memory. It only creates the numbers when needed.
Examples of range() function
Let's discuss each example of range() function below:
1. Stop parameter
for i in range(5):print(i)
Code explanation: range(5) creates a sequence of numbers from 0 to 4. The loop will run 5 times, printing numbers starting from 0 to 4.
2. Start and stop parameters
for i in range(2, 6):print(i)
Code explanation: The loop starts at 2 and stops at 5. The loop will run 4 times, printing numbers starting from 2 to 5.
3. Start, stop, and step parameters
for i in range(1, 10, 2):print(i)
Code explanation: We used all three parameters: start, stop, and step. The loop starts at 1, increments by 2 each time (due to the step value), and stops before reaching 10.
What happens when you reverse the step value? Try experimenting with these changes and observe the change in the output.
This will help deepen your understanding of how range() handles different parameters and how it can be used to create loops that count downwards.
xrange() function
The xrange() function is available only in Python 2. It works like range(), but it returns a generator object instead of a list. This means it creates numbers one at a time when needed, making it very efficient for large ranges.
Syntax of xrange() function
The syntax of xrange() is the same as range():
xrange(stop)xrange(start, stop)xrange(start, stop, step)
Parameters of xrange() function
start: The first number in the sequence (optional, defaults to 0).stop: The point where the sequence stops (required, but not included in the sequence).step: The amount to increase or decrease in each step (optional, defaults to 1).
Efficiency of xrange() function
xrange() is memory efficient because it generates numbers on demand. However, it is slower than Python 3’s range() because it needs to reconstruct the numbers repeatedly during iteration.
Examples of xrange() function
Let's discuss each example of xrange() function below:
1. Stop parameter
for i in xrange(5):print(i)
Code explanation: The xrange(5) creates a generator that produces numbers from 0 to 4. Since this is Python 2, the loop will produce the same result as range(), but it does not store all numbers in memory at once, making it more efficient for large sequences.
2. Start and stop parameters
for i in xrange(2, 6):print(i)
Code explanation: Just like with range(), this creates a sequence starting from 2 and ending before 6.
3. Start, stop, and step parameters
for i in xrange(1, 10, 2):print(i)
Code explanation: We used all three parameters (start, stop, and step). The generator object created by xrange() will produce numbers from 1 to 9, skipping every second number because of the step value of 2.
Comparison between range() and xrange()
Let's discuss the difference between range() and xrange() below:
Feature |
|
|
Usage | Used in Python 3 | Used in Python 2 |
Return Value | Returns a range object (immutable sequence) | Returns a generator object |
Memory Consumption | Efficient in Python 3 | More memory-efficient for large ranges |
Speed | Faster than | Slower because it reconstructs numbers |
Backward Compatibility | Can work in both Python 2 and 3 | Only works in Python 2 |
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