Basic multipliers
Input
funcs = generate_multipliers([1, 2, 3]) funcs[1](5)
Output
10
The second generated function multiplies by 2, so funcs[1](5) returns 10.
Full lesson preview
Fix Late Binding in Loop Generated Functions
Learn to build function factories that correctly capture loop variables. Fix the common late-binding bug when creating functions inside loops.
Python practice15 minClosures & Function FactoriesIntermediateLast updated April 13, 2026
Problem statement
When creating functions inside a loop that reference the loop variable, all generated functions can accidentally share the same final value of that variable — a problem known as late binding. Your task is to implement generate_multipliers(factors), which accepts a list of numeric factors and returns a list of functions. Each returned function should take a single argument x and return x multiplied by the factor that was current when that function was created. You must ensure each function captures its own factor (no late binding).
Task
Implement a closure-based factory that returns a list of functions where each function captures the loop variable at creation time (no late-binding issues).
Examples
Input format
A single call to generate_multipliers with a list of numeric factors; then a call to one of the returned functions with a numeric input. For tests, expressions like generate_multipliers([2,3])[1](4) are used.
Output format
A single numeric value: the result of calling the selected multiplier function.
Constraints
factors is a list of integers or floats. The returned functions should work for integer and float inputs. Expected length of factors is typically small (<= 1000). Do not use global variables. Implement the closure correctly so each function retains its own factor.
Samples
Sample 1
Input
generate_multipliers([2, 3, 5])[2](4)
Output
20
The third function multiplies by 5, so passing 4 returns 20.