Python range() 函数

Python range() 函数生成一个数字序列。

默认情况下，序列从 0 开始，递增 1，并在指定数字之前停止。

# create a sequence from 0 to 3
numbers = range(4)

# iterating through the sequence
for i in numbers:
    print(i)

0
1
2
3

range() 语法

range(start, stop, step)

start 和 step 参数是可选的。

range() 返回值

range() 函数返回一个不可变的数字序列。

示例 1：range(stop)

# create a sequence from 0 to 3 (4 is not included)
numbers = range(4)

# convert to list and print it
print(list(numbers))    # Output: [0, 1, 2, 3]

在此示例中，我们已将 range 序列转换为列表。

示例 2：range(start, stop)

# create a sequence from 2 to 4 (5 is not included)
numbers = range(2, 5)
print(list(numbers))    # [2, 3, 4]

# create a sequence from -2 to 3
numbers = range(-2, 4)    
print(list(numbers))    # [-2, -1, 0, 1, 2, 3]

# creates an empty sequence
numbers = range(4, 2) 
print(list(numbers))    # []

示例 3：range(start, stop, step)

# create a sequence from 2 to 10 with increment of 3
numbers = range(2, 10, 3)
print(list(numbers))    # [2, 5, 8]

# create a sequence from 4 to -1 with increment of -1
numbers = range(4, -1, -1)    
print(list(numbers))    # [4, 3, 2, 1, 0]

# range(0, 5, 1) is equivalent to range(5)
numbers = range(0, 5, 1) 
print(list(numbers))    # [0, 1, 2, 3, 4]

for 循环中的 range()

range() 函数通常用于for 循环中，以迭代特定次数的循环。例如，

# iterate the loop five times
for i in range(5):
    print(f'{i} Hello')

0 Hello
1 Hello
2 Hello
3 Hello
4 Hello

另请阅读

• Python list()