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Numpy – Print Array With Commas

The Numpy library in Python comes with a number of useful functions to work with and manipulate arrays. In this tutorial, we will look at how to print a numpy array with elements separated by commas with the help of some examples.

Printing a Numpy Array

First, let’s see what we get when we directly print a numpy array.

import numpy as np

# create numpy array
ar = np.array([1, 2, 3, 4, 5])
# print the array
print(ar)

Output:

[1 2 3 4 5]

Here, we created a numpy array of five numbers and then printed it using the print() function. You can see that the elements are printed with a space between them.

How to print a numpy array with commas?

print numpy array with commas

You can use the numpy array2string() function to print a numpy array with elements separated by commas. Pass the array and the separator you want to use (“,” in our case) to the array2string() function.

The following is the syntax –

# print numpy array with "," separator
print(np.array2string(ar, separator=","))

It returns a string representation of the array with the given separator.

Let’s now apply this function to the above array such that its elements are separated by commas on printing.

# print array with "," as separator
print(np.array2string(ar, separator=","))

Output:

[1,2,3,4,5]

The array elements are separated by commas.

If the printed array looks cluttered, you can specify , (a comma followed by a space) as the separator.

# print array with ", " as separator
print(np.array2string(ar, separator=", "))

Output:

[1, 2, 3, 4, 5]

The elements now look less cluttered.

Use the repr() function

Alternatively, you can use the Python built-in repr() function to print a numpy array with commas. The repr() function is used to print the string representation of an object in Python.

Let’s look at an example.

print(repr(ar))

Output:

array([1, 2, 3, 4, 5])

The array elements are separated by commas. Note that the output is not exactly the same as what we got with the array2string() function.

Summary – Print Numpy Array with Comma as a Separator

In this tutorial, we looked at how to print a numpy array with a comma as a separator. The following are the steps mentioned in this tutorial –

  • Create a numpy array (skip this step if you already have a numpy array to operate on).
  • Use the numpy array2string() function to get a string representation of the array with the desired separator (a comma in our case).
    There are alternative methods as well, such as using the repr() function.

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Author

  • Piyush

    Piyush is a data scientist passionate about using data to understand things better and make informed decisions. In the past, he's worked as a Data Scientist for ZS and holds an engineering degree from IIT Roorkee. His hobbies include watching cricket, reading, and working on side projects.