在zip（）的for循环中使用lambda

Question

Hello guys I've been playing today a bit with python and got a bit confused while using the lambda fucntion. My original intention was to subtract the value of each element in a vector with the values form a second vector and introduce all the results in a 3rd vector. Went like this:

v1=[1, 2, 3, 4]
v2 =[7,2 ,7 ,6]
v3=[x-y for x,y in zip(v1,v2)]

then I though to calculate using the same structure the absolute value using a lambda function and I tried this:

v1=[1, 2, 3, 4]
v2 =[7,2 ,7 ,6]
[lambda x,y: x-y if x>y else y-x for x,y in zip(v1,v2)]

this only gives memory locations I think. and I don't know why , wehre I did wrong?

Answer 1

It gives you a bunch of lambda functions. All you did there is define the function, but you never call it. Do this instead:

[(lambda x,y: x-y if x>y else y-x)(x,y) for x,y in zip(v1,v2)]

You really don't need a function, though. Just do it like this:

[(x-y if x>y else y-x) for x,y in zip(v1,v2)]