Python's equivalent for R's dput() function

Question

Is there any function in python similar to dput() function in R?

Answer 1

This answer focuses on json.dump() and json.dumps() and how to use them with numpy arrays. If you try, Python will hit you with an error saying that ndarrays are not JSON serializable:

import numpy as np
import json

a = np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
json.dumps(a)

TypeError: Object of type 'ndarray' is not JSON serializable

You can avoid this by translating it to a list first. See below for two working examples:

json.dumps()

json.dumps() seems to be the closest to R's dput() since it allows you to copy-paste the result straight from the console:

json.dumps(a.tolist()) # '[[1, 2, 3], [4, 5, 6], [7, 8, 9]]'

json.dump()

json.dump() is not the same as dput() but it's still very useful. json.dump() will encode your object to a json file.

# Encode:
savehere = open('file_location.json', 'w')
json.dump(a.tolist(), savehere)

which you can then decode elsewhere:

# Decode:
b = open('file_location.json', 'r').read()   # b is '[[1, 2, 3], [4, 5, 6], [7, 8, 9]]'
c = json.loads(b)

Then you can transform it back a numpy array again:

c = np.array(c)

More information

on avoiding the 'not serializable' error see:

• numpy array is not json serializable

• how to make classes json serializable (kind of unrelated, but very interesting)