Question: I'm trying to write a function in python that is like:

```
def repeated(f, n):
    ...

```

where `f` is a function that takes one argument and `n` is a positive integer.

For example if I defined square as:

```
def square(x):
    return x * x

```

and I called

```
repeated(square, 2)(3)

```

this would square 3, 2 times.

Answer: 
Use an itertools recipe called `repeatfunc` that performs this operation.

**Given**

```
def square(x):
    """Return the square of a value."""
    return x * x

```

**Code**

From [itertools recipes](https://docs.python.org/3/library/itertools.html#itertools-recipes):

```
def repeatfunc(func, times=None, *args):
    """Repeat calls to func with specified arguments.

    Example:  repeatfunc(random.random)
    """
    if times is None:
        return starmap(func, repeat(args))
    return starmap(func, repeat(args, times))

```

**Demo**

Optional: You can use a third-party library, [`more_itertools`](https://github.com/erikrose/more-itertools), that conveniently implements these recipes:

```
import more_itertools as mit

list(mit.repeatfunc(square, 2, 3))
# [9, 9]

```

Install via `> pip install more_itertools`
Here's a recipe using `reduce`:

```
def power(f, p, myapply = lambda init, g:g(init)):
    ff = (f,)*p # tuple of length p containing only f in each slot
    return lambda x:reduce(myapply, ff, x)

def square(x):
    return x * x

power(square, 2)(3)
#=> 81

```

I call this `power`, because this is literally what the power function does, with composition replacing multiplication.

`(f,)*p` creates a tuple of length `p` filled with `f` in every index. If you wanted to get fancy, you would use a generator to generate such a sequence (see `itertools`) - but note it would have to be created inside the lambda. 

`myapply` is defined in the parameter list so that it is only created once.