Avoiding nested for loops

Question

I am trying to test some other Python code repeatedly, using all possible combinations of values for six different parameters. For each parameter I want to iterate over a range of values with a given minimum, maximum and step. I managed to write some code like: ``` for var1 in range(min1, max1, step1): for var2 in range(min2, max2, step2): for var3 in range(min3, max3, step3): for var4 in range(min4, max4, step4): for var5 in range(min5, max5, step5): for var6 in range(min6, max6, step6): do_something_with(var1, var2, var3, var4, var5, var6) ``` But I do not like that the code is so deeply nested. How can I avoid nesting multiple loops? Can it be done using recursion? How about `itertools.product`? I wasn't able to figure out either approach. See also, more generally: Get the cartesian product of a series of lists? This question, and some answers, originally showed code for Python 2.x. It has been edited because the fundamental problem persists in 3.x, with the same solution, but `xra…

Accepted Answer

Here's how to use `product`:

```
x1 = range(min1, max1, step1)
x2 = range(min2, max2, step2)
x3 = range(min3, max3, step3)
...

for v1, v2, v3, v4, v5, v6 in itertools.product(x1, x2, x3, x4, x5, x6):
    do_something_with(v1, v2, v3, v4, v5, v6)
```

or a bit more compactly:

```
ranges = [
    range(min1, max1, step1),
    range(min2, max2, step2),
    range(min3, max3, step3),
    ...
]

for v1, v2, v3, v4, v5, v6 in itertools.product(*ranges):
    do_something_with(v1, v2, v3, v4, v5, v6)
```

Avoiding nested for loops

Solution

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