To print numpy objects without line breaks, you can use np.array_repr() with .replace() methods or np.array2string() with formatting.

When dealing with large arrays and needing to print the entire array for debugging, the default printing with line breaks can consume a significant amount of vertical space.

Printing without line breaks provides a more compact representation.

With line breaks, the numpy array (object) looks like this:

Without line breaks, the numpy array (object) looks like this:

Method 1: Using np.array_repr() with .replace()

The numpy.array_repr() function converts an array into a string, returning a string representation of the array. 

After converting it into a string, we can further apply the .replace() function to replace the line break character (“\n”) with an empty space(“), effectively removing the line breaks.

import numpy as np

arr = np.array([[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12]])

# Printing an array (with line breaks)
print("With line breaks:")
print(arr)

# Printing an array without line breaks (using np.array_repr and replace)
print("\nWithout line breaks:")
arr_str = np.array_repr(arr).replace('\n', '')
print(arr_str)

Output

With line breaks:
[[ 1  2  3  4]
 [ 5  6  7  8]
 [ 9 10 11 12]]

Without line breaks:
array([[ 1,  2,  3,  4],       [ 5,  6,  7,  8],       [ 9, 10, 11, 12]])

Method 2: Using np.array2string() with formatting

The np.array2string() method also does the same conversion as the np.array_repr() function, which converts an array into a string, except allowing us to specify the separator between elements.

Then, we can use the .replace() method to replace line breaks with an empty string.

import numpy as np

arr = np.array([[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12]])

# Printing an array (with line breaks)
print("With line breaks:")
print(arr)

# Printing without line breaks (using np.array2string with replace())
print("\nWithout line breaks (using array2string):")
arr_str_2 = np.array2string(arr, separator=', ').replace('\n', '')
print(arr_str_2)

Output

With line breaks:
[[ 1  2  3  4]
 [ 5  6  7  8]
 [ 9 10 11 12]]

Without line breaks (using array2string):
[[ 1,  2,  3,  4], [ 5,  6,  7,  8], [ 9, 10, 11, 12]]

That’s all!