For all noobs like me. If you get this error, you most probably doing one stupid thing like I did:

```
y2 = []
for x in y2.shape[0]:
y2.append(x[0])
```

where *y2.shape[0]* is just an integer. Remember, we can iterate only through lists or other sequences. When we would like to repeat a certain action X number of times we should do the following:

```
y2 = []
for x in range(y2.shape[0]):
y2.append(x[0])
```

If you, let’s say, have an array ‘a’ and would like to iterate through, then:

for i in a[:,0]:

print(i)

Would actually print all the items in the array first column *(: -from start to end, 0 -first column)*

This:

for i in len(a[:,0]):

print(i)

Will result in an error. But this will actually work as expected:

for i in range(len(a[:,0])):

print(i)

Because *range(len(a[:,0]))* is an object: *range(0, 96). *

So please be careful here, haha! 🙂