CODEWITHSUNDEEP
pythonpython-3.xlambda
Hardik Gupta
Hardik Gupta

Reputation: 4790

Lambda function with 3 arguments in Python

I am using a lambda function to check the highest value, passing 3 arguments

from functools import reduce

# function to check bigger item
f = lambda a,b,c: a if (a > b) else (b if (b > c) else c)

# reduce function
reduce(f, [47, 11, 42, 102, 13])

However I get an error like this

TypeError Traceback (most recent call last)

5 
6 # reduce function
7 reduce(f, [47, 11, 42, 102, 13, 21])

TypeError: <lambda>() missing 1 required positional argument: 'c'

Upvotes: 1

Views: 2410

Answers (3)

kederrac
kederrac

Reputation: 17322

for checking the highest value use the build-in function max:

max([47, 11, 42, 102, 13])

Upvotes: 1

ComplicatedPhenomenon
ComplicatedPhenomenon

Reputation: 4199

If you are looking for the biggest elements in the list, compare three elements in once works in the same way as compare two elements in once. the two ways cost the same time. and even you make a function like reduce but takes 3 elements a time, there is a defect in your idea, because what if the list is composed of 4 or 6 or 8 or... elements, It still won't work as you expected.

from functools import reduce

# function to check bigger item
g = lambda a,b: a if (a > b) else b 
f(1,3,4)
# reduce function
reduce(g, [47, 11, 42, 102, 13])

Upvotes: 3

Alberto de Blas
Alberto de Blas

Reputation: 58

From: https://docs.python.org/3/library/functools.html

functools.reduce(function, iterable[, initializer])

Apply function of two arguments cumulatively to the items of sequence, from left to right, so as to reduce the sequence to a single value.

So, reduce is designed for functions with 2 arguments.

Upvotes: 2

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