The difference between range and xrange in Python ·

Range
Function Description: Range ([Start,] stop[, step]), which generates a sequence based on the range specified by start and stop and step set by step.
Range Example:

2. >>> Range(5)
4. [0, 1, 2, 3, 4]
6. >>> Range(1,5)
8. [1, 2, 3, 4]
10. >>> Range(0,6,2)
12. [0, 2, 4]

Xrange
Function Description: The usage is exactly the same as range, the difference is not an array, but a builder.
xrange Example:

2. >>> xrange(5)
4. Xrange(5)
6. >>> list(xrange(5))
8. [0, 1, 2, 3, 4]
10. >>> xrange(1,5)
12. Xrange(1, 5)
14. >>> list(xrange(1,5))
16. [1, 2, 3, 4]
18. >>> xrange(0,6,2)
20. Xrange(0, 6, 2)
22. >>> list(xrange(0,6,2))
24. [0, 2, 4]

As can be known from the above example: to generate a large number sequence, using xrange will be much better than range performance, because there is no need to open up a large amount of memory space, both of which are basically used in the loop:

1. for I in range(0, + ):
2. Print i
3. for I in xrange(0, + ):
4. Print i

The results of both outputs are the same, in fact there are many differences, and range generates a list object directly:

1. A = range(0,+)
2. Print type(a)
3. Print a
4. Print a[0], a[1]

Output Result:

2. <type  ' list ' >
4. [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60  3, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99]
6. 0 1

Xrange does not generate a list directly, but instead returns one of the values for each call:

1. A = xrange(0,+)
2. Print type(a)
3. Print a
4. Print a[0], a[1]

Output Result:

1. <type ' xrange '>
2. Xrange (100)
3. 0 1

So xrange do loop performance better than range, especially when returning very large, try to use Xrange bar, unless you are going to return a list.

Article reproduced from http://ciniao.me/article.php?id=17

The difference between range and xrange in Python ·