# Range

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The Python `range()` function returns a sequence of numbers. It is commonly used as part of a `for` loop.

`range(start, stop, step)`

• `start` – optional, default is 0
• `stop`required
• `step` – optional, default is 1

### Loop pattern

The `range()` function is commonly used to loop over some code a specific number of times.

``````for i in range(10):
print(i)``````

The above code will print each number in the range [0, 9] inclusive. Note that `range(10)` begins at 0 and stops at 9 – a total of 10 numbers but not including the number 10.

### Multiple parameters

`range()` may be called with a single bounding parameter, as in `range(stop)`. The returned sequence will begin at zero and count up by 1 until the bound (not including it). For example, `range(4)` would include 0, 1, 2, and 3, but not 4.

When using two parameters, the function operates as `range(start, stop)`. The `start` parameter specifies the first number of the sequence, and `stop` works as before by bounding the sequence. So `range(2, 5)` would include 2, 3, and 4, but not 5.

Finally, a function call with three parameters is done by `range(start, stop, step)`. The `step` parameter specifies the incrementation between each consecutive number in the sequence, beginning at the starting number. As an example, `range(0, 6, 2)` would include 0, 2, and 4 (6 is the upper bound, so is not included).