# How to access a NumPy array by column

• Difficulty Level : Easy
• Last Updated : 29 May, 2021

Accessing a NumPy based array by a specific Column index can be achieved by the indexing. Let’s discuss this in detail.

NumPy follows standard 0 based indexing.

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Row and column in NumPy are similar to Python List

Examples:

```Given array : 1 13 6
9  4 7
19 16 2

Input: print(NumPy_array_name[ :,2])

# printing 2nd column
Output: [6 7 2]

Input: x =  NumPy_array_name[ :,1]
print(x)

# storing 1st column into variable x
Output:  [13 4 16]```

Method #1: Selection using slices

Syntax :

For column : numpy_Array_name[  : ,column]

For row : numpy_Array_name[ row, :  ]

## Python3

 `# Python code to select row and column``# in NumPy` `import` `numpy as np` `array ``=` `[[``1``, ``13``, ``6``], [``9``, ``4``, ``7``], [``19``, ``16``, ``2``]]` `# defining array``arr ``=` `np.array(array)` `print``(``'printing array as it is'``)``print``(arr)` `print``(``'printing 0th row'``)``print``(arr[``0``, :])` `print``(``'printing 2nd column'``)``print``(arr[:, ``2``])` `# multiple columns or rows can be selected as well``print``(``'selecting 0th and 1st row simultaneously'``)``print``(arr[:,[``0``,``1``]])`

Output :

```printing array as it is
[[ 1 13  6]
[ 9  4  7]
[19 16  2]]
printing 0th row
[ 1 13  6]
printing 2nd column
[6 7 2]
selecting 0th and 1st row simultaneously
[[ 1 13]
[ 9  4]
[19 16]]```

Method #2: Using Ellipsis

Syntax :

For column : numpy_Array_name[,column]

For row : numpy_Array_name[row,]

where ‘‘ represents no of elements in the given row or column

Note: This is not a very practical method but one must know as much as they can.

## Python3

 `# program to select row and column``# in numpy using ellipsis` `import` `numpy as np` `# defining array``array ``=` `[[``1``, ``13``, ``6``], [``9``, ``4``, ``7``], [``19``, ``16``, ``2``]]` `# converting to numpy array``arr ``=` `np.array(array)` `print``(``'printing array as it is'``)``print``(arr)` `print``(``'selecting 0th column'``)``print``(arr[..., ``0``])` `print``(``'selecting 1st row'``)``print``(arr[``1``, ...])`

Output :

```printing array as it is
[[ 1 13  6]
[ 9  4  7]
[19 16  2]]
selecting 0th column
[ 1  9 19]
selecting 1st row
[9 4 7]```

My Personal Notes arrow_drop_up