What does .shape[] do in “for i in range(Y.shape[0])”?

Question

I\'m trying to break down a program line by line. Y is a matrix of data but I can\'t find any concrete data on what .shape[0] does exactly.

Answer 1

In python, Suppose you have loaded up the data in some variable train:

train = pandas.read_csv('file_name')
>>> train
train([[ 1.,  2.,  3.],
        [ 5.,  1.,  2.]],)

I want to check what are the dimensions of the 'file_name'. I have stored the file in train

>>>train.shape
(2,3)
>>>train.shape[0]              # will display number of rows
2
>>>train.shape[1]              # will display number of columns
3