CODEWITHSUNDEEP
pythonhigher-order-functions
user16984591
user16984591

Reputation:

how do i pass argument into a function inside a function?

My string of code currently is:

def makeTriangle(sign):
    
    def triangle(n):
        result = ''
    
        for i in range(1,n+1):
            result += sign * i + '\n'
        
        return result
    
    return

how do i actually pass the sign from MakeTriangle(sign) into triangle(n) using higher order function?

Upvotes: 0

Views: 110

Answers (1)

2e0byo
2e0byo

Reputation: 5954

You just need to return triangle otherwise it's thrown away. Since this pattern seems to cause some confusion:

def makeTriangle(sign):
    
    def triangle(n):
        result = ''
    
        for i in range(1,n+1):
            result += sign * i + '\n'
        
        return result
    
    return triangle # returns a function wrapped in an enclosing scope


triangle_maker = makeTriangle("+")
# triangle_maker is a `triangle()` function, locked in a scope where `sign=+`.
triange_maker(3)
# calls the `triangle()` function

The other option for this pattern is to use functools.partial:

from functools import partial

def triangle(sign, n):
    result = ""
    for i in range(1, n+1):
        result += sign * i + "\n"
    return result

# call without caching arg:
triangle("+",3)
# make partial function:
plus_triangle = partial(triangle, "+")
plus_triangle(3)

This saves one having to write out the container function every time, but it is of course much more limited than a full closure.

Upvotes: 1

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