[FIXED] Pass non-iterable variables to a function evaluated with map()

Issue

I am working in python and trying to convert a function with this structure:

def func(g,h,iterable):
 return iterable*(g+h)

for iterable in range(20):
  print func(2,3,iterable)

Into a mapped function:

def func(g,h,iterable):
 return iterable*(g+h)

print map(func,2,3,range(20)) #does not work...

The issue I am having is passing constants through the map() function, currently I don't know how to do it.

I want this structure so I can easily use the Ipython parallelism tools.

Assume:

• The actual function completion over all iterables takes ~1.5hr (thus the desire for using a parallel map() function
• The function is complex and cannot use list comprehension

Essentially, if it wasn't already obvious I am a MATLAB programmer making the leap to python and looking for a good substitute for the parfor function in matlab.

Solution

For one thing, if you map your function over a range, no parameter is an iterable.

To your question, you can bind positional parameters (from left to right) to a function using functools.partial

def func(g,h,i):
    return i*(g+h)

print map(functools.partial(func, 2,3), range(20))

# [0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95]

For binding any positional parameter, use a lambda expression like stated in hkpeprah's answer.

Answered By - Thomas Fenzl