Python3 range() function usage

Python3 内置函数Python3 built-in functions

Python3 range() function returns an iterable object (the type is object), not a list type, so it won't print a list when printed.

Python3 list() function is an object iterator that can convert the iterable object returned by range() into a list, and the returned variable type is a list.

Python2 range() functionReturns a list.

Function syntax

range(stop)
range(start, stop[, step])

Parameter description:

  • start: Counting starts from start. The default is to start from 0. For example, range(5) is equivalent torange(0， 5)
  • stop: Counting ends at stop, but does not include stop. For example: range(0, 5) is [0, 1, 2, 3, 4] without 5
  • step: Step size, defaults to1. For example: range(0, 5) is equivalent to range(0, 5, 1)

Example

If only the start and end values are provided, the step size defaults to 1:

Example

for number in range(1, 6):
    print(number)

The output result is:

1
2
3
4
5

If only one parameter is provided, it generates a sequence of integers starting from 0, with the parameter as the end value and the step size defaulting to 1:

Example

for number in range(6):
    print(number)

The output result is:

0
1
2
3
4
5

You can specify the step size to increment by different amounts each time:

Example

for number in range(1, 6, 2):
    print(number)

The output result is:

1
3
5

Note: The end value 6 is not included.

Additionally, we can use a negative number as the step size to generate a sequence in reverse order from the end value:

Example

for number in range(6, 1, -1):
    print(number)

The output result is:

6
5
4
3
2

Note:If a negative number is used as the step size, the start value must be greater than the end value.

If you only need to generate a sequence of integers and do not need to use a for loop to iterate over it, you can convert the return value of the range() function to a list or tuple, for example:

The following generates a list of integers:

Example

>>> numbers = list(range(1, 6))
>>> numbers
[1, 2, 3, 4, 5]

The following generates a tuple of integers:

Example

>>> numbers = tuple(range(1, 6))
>>> numbers
(1, 2, 3, 4, 5)

Python3 内置函数Python3 built-in functions

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