CODEWITHSUNDEEP
pythonpython-3.xnumpynumpy-slicing
CapKoko
CapKoko

Reputation: 59

I don't know the meaning of the code "[:, row:row]"

I have the code:

g, g_err = data[:, 4:6].T

I don't know the meaning of [:, 4:6]

especially the first :

and does .T mean transpose?

Upvotes: 1

Views: 135

Answers (1)

lenik
lenik

Reputation: 23546

You have a 2D matrix called data, your code takes all elements from the first dimension, marked as :, then takes only elements 4 and 5 in the second dimension, something like this:

>>> np.ones( (7,7 ))
array([[ 1.,  1.,  1.,  1.,  1.,  1.,  1.],
       [ 1.,  1.,  1.,  1.,  1.,  1.,  1.],
       [ 1.,  1.,  1.,  1.,  1.,  1.,  1.],
       [ 1.,  1.,  1.,  1.,  1.,  1.,  1.],
       [ 1.,  1.,  1.,  1.,  1.,  1.,  1.],
       [ 1.,  1.,  1.,  1.,  1.,  1.,  1.],
       [ 1.,  1.,  1.,  1.,  1.,  1.,  1.]])
>>> np.ones( (7,7 ))[:,4:6]
array([[ 1.,  1.],
       [ 1.,  1.],
       [ 1.,  1.],
       [ 1.,  1.],
       [ 1.,  1.],
       [ 1.,  1.],
       [ 1.,  1.]])
>>>

And yeah, .T means transpose.

Upvotes: 1

Related Questions