Lambda Expresion

Developers
#1

Hello,

how can i interate with a lambda expresion thrue a list?

 import sys
 import clr
 clr.AddReference('ProtoGeometry')
 from Autodesk.DesignScript.Geometry import *


 mal = lambda x,y: x*y
 plus = lambda x,y: x+y

  OUT = mal(IN[0],IN[1]),plus(IN[0],IN[1])

2021-01-12_16h36_01
2021-01-12_16h36_01997×860 185 KB

KR

Andreas

#2

@Draxl_Andreas You need to induce a for loop to iterate through the list.
See if this helps you understand.

image
image1004×660 78.7 KB

mal = lambda x,y: x*y
plus = lambda x,y: x+y

#To make sure code works with 1 number and also a list of numbers
toList = lambda x : x if hasattr(x, '__iter__') else [x]

#To store the results
mul = []
add = []

#To iterate through all values in a list
for num1,num2 in zip(toList(IN[0]),toList(IN[1])):
	mul.append(mal(num1,num2))
	add.append(plus(num1,num2))

OUT = mul,add
1 Like
#3

thank you! what is “–iter–” in that case a buildinfuction ?

#4

@Draxl_Andreas
Iterator (iter) in Python is simply an object that can be iterated upon. An object which will return data, one element at a time. You need an iterator while implementing a for loop or it will throw error.

So what we are doing is essentially checking if the input has an attribute iter
(in simplest form: it helps to checks if the input is a part of some sort of list from which the values can be called one after another)

Alternatively, you can use something like

toList = lambda x : x if isinstance(x,list) else [x]

But it is recommended using the hasattr(x, ‘iter’) since it is more robust.

1 Like