lambda 表达式相对于常规 function 的优势是什么？

Question

From the docs :

Unlike lambda forms in other languages, where they add functionality, Python lambdas are only a shorthand notation if you're too lazy to define a function.

Is there an actual advantage using lambda expression over regular functions like a runtime advantage or an aesthetic one? Is there cases where lambda expression are an absolute necessity? I feel like they are just a limited version of functions as they can contain only 1 argument.

I'am not sure to grasp their utility and the concept as a whole beyond the fact that it's an implementation of Alonso Church lambda calculus.

The following compute the product of 2 numbers, and I find the function version clearer.

def myfunc(n):
  return lambda a : a * n

mydoubler = myfunc(2)

print(mydoubler(11))

def times(a,b):
    return a*b

print (times(2,11))

Answer 1

Lambdas can have multiple arguments. A place I find they fit nicely is when I'm creating functional dictionaries. Ex:

res = input("Unexpected Input Here")

choices = {
    "x": lambda *data: data[1] / data[0]
    "y": lambda *data: data[1] - data[0],
    "z": lambda data1, data2: data2 * data1
    ...
}

choices[res](100, 20)

It's not worth it for me to write these out to multiple functions. This is a fairly trivial example but I use this pattern for HTTP request validation, pandas data manipulation, etc. It's great because you can also iterate over dictionaries and you can create a pipeline of functions (based on specialized logic to skip certain keys, potentially based on the value instance via isinstance ).