Finding the max and min in a tuple of tuples

Question

I'm new to python and having some problems finding the minimum and maximum values for a tuple of tuples. I need them to normalise my data. So, basically, I have a list that is a row of 13 numbers, each representing something. Each number makes a column in a list, and I need the max and min for each column. I tried indexing/iterating through but keep getting an error of

max_j = max(j)

TypeError: 'float' object is not iterable

any help would be appreciated!

The code is (assuming data_set_tup is a tuple of tuples, eg ((1,3,4,5,6,7,...),(5,6,7,3,6,73,2...)...(3,4,5,6,3,2,2...)) I also want to make a new list using the normalised values.

normal_list = []

for i in data_set_tup:

    for j in i[1:]: # first column doesn't need to be normalised
        max_j = max(j)
        min_j = min(j)
        normal_j = (j-min_j)/(max_j-min_j)
        normal_list.append(normal_j)
    normal_tup = tuple(normal_list)

Answer 1

You can transpose rows to columns and vice versa with zip(*...). (Use list(zip(*...)) in Python 3)

cols = zip(*data_set_tup)
normal_cols = [cols[0]] # first column doesn't need to be normalised
for j in cols[1:]:
    max_j = max(j)
    min_j = min(j)
    normal_cols.append(tuple((k-min_j)/(max_j-min_j) for k in j)

normal_list = zip(*normal_cols)