# Get the First N Columns of a 2D Numpy Array

The Numpy library in Python comes with a number of useful methods and techniques to work with and manipulate data in arrays. In this tutorial, we will look at how to get the first N columns of a two-dimensional Numpy Array with the help of some examples.

## How to get the first n columns of a 2D Numpy array?

You can use slicing to get the first N columns of a 2D array in Numpy. Here, we use column indices to specify the range of columns that we’d like to slice. To get the first n columns, use the following slicing syntax –

```# first n columns of numpy array
ar[:, :n]```

It returns the first n columns (including all the rows) of the given array.

## Steps to get the first n columns of 2D array

Let’s now look at a step-by-step example of using the above syntax on a 2D Numpy array.

### Step 1 – Create a 2D Numpy array

First, we will create a 2D Numpy array that we’ll operate on.

```import numpy as np

# create a 2D array
ar = np.array([
['Tim', 181, 86],
['Peter', 170, 68],
['Isha', 158, 59],
['Rohan', 168, 81],
['Yuri', 171, 65],
['Emma', 166, 64],
['Michael', 175, 78],
['Jim', 190, 87],
['Pam', 168, 57],
['Dwight', 187, 84]
])
# display the array
print(ar)```

Output:

```[['Tim' '181' '86']
['Peter' '170' '68']
['Isha' '158' '59']
['Rohan' '168' '81']
['Yuri' '171' '65']
['Emma' '166' '64']
['Michael' '175' '78']
['Jim' '190' '87']
['Pam' '168' '57']
['Dwight' '187' '84']]```

Here, we used the `numpy.array()` function to create a 2D Numpy array with 10 rows and 3 columns. The array contains information on the height (in cm) and weight (in kg) of some employees in an office.

### Step 2 – Slice the array to get the first n columns

To get the first n columns of the above array, slice the array starting from the first column (0th index) up to (but not including) the column with the nth index.

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For example, let’s get the first 2 columns from the array that we created in step 1.

```# first 2 columns
print(ar[:, 0:2])```

Output:

```[['Tim' '181']
['Peter' '170']
['Isha' '158']
['Rohan' '168']
['Yuri' '171']
['Emma' '166']
['Michael' '175']
['Jim' '190']
['Pam' '168']
['Dwight' '187']]```

We get the first 2 columns of the 2D array.

In the above code, you don’t need to explicitly specify 0 (since you’re slicing starting from the very first column of the array).

```# first 2 columns
print(ar[:, :2])```

Output:

```[['Tim' '181']
['Peter' '170']
['Isha' '158']
['Rohan' '168']
['Yuri' '171']
['Emma' '166']
['Michael' '175']
['Jim' '190']
['Pam' '168']
['Dwight' '187']]```

We get the same result as above.

For more on slicing Numpy arrays, refer to its documentation.

## Summary

In this tutorial, we looked at how to get the first n columns of a two-dimensional Numpy array using slicing. The following is a short summary of the steps mentioned in the tutorial.

1. Create a 2D Numpy array (skip this step if you already have an array to operate on).
2. Slice the array from the column with index 0 to the column with index n (but not including it) to get the first n columns of the array.

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