I want to add the numbers 1,2,3 from the below list of tuples together. I tried:
reduce(lambda (x,y),(z,t): y+t,[('a',1),('b',2),('c',3)])
I get an error:
TypeError: 'int' object is not iterable
How do I fix this error? Thank you
You are trying to add a list of tuples. Therefore your lambda must return a tuple (otherwise, how will you add one call's result to the next item?), and you must also use a starting value that is a tuple. Something like this works:
reduce(lambda (x,y),(z,t): (0, y+t),[('a',1),('b',2),('c',3)], (0,0))[1]
You end up with a tuple (0, 6) and then use [1] to just get the 6.
If that looks ugly, it's because reduce is not a great tool for this. sum with a generator expression works much better:
sum(x[1] for x in [('a',1),('b',2),('c',3)])