I'm trying to build a code that checks whether a given object is an np.array() in python.
if isinstance(obj,np.array()) doesn't seem to work.
I would truly appreciate any help.
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4np.ndarray, not np.array(): stackoverflow.com/a/36783987/483620Benjamin– Benjamin2019-12-11 06:17:29 +00:00Commented Dec 11, 2019 at 6:17
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Want to be mindful of subclasses too.Benjamin– Benjamin2019-12-11 06:23:04 +00:00Commented Dec 11, 2019 at 6:23
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4 Answers
isinstance(obj, numpy.ndarray) may work
Comments
You could compare the type of the object being passed to the checking function with 'np.ndarray' to check if the given object is indeed an np.ndarray
The sample code snippet for the same should look something like this :
if isinstance(obj,np.ndarray):
# proceed -> is an np array
else
# Not an np.ndarray
1 Comment
Perkins
isinstance is the proper check in almost every case. This code will fail if value is an instance of a subclass of numpy.ndarray.Below code seems to work. Use numpy.ndarray.
import numpy as np
l = [1,2,3,4]
l_arr = np.array(l)
if isinstance(l_arr, np.ndarray):
print("Type is np.array")
else:
print("Type is not np.array")
Output:
Type is np.array
Comments
The type of what numpy.array returns is numpy.ndarray. You can determine that in the repl by calling type(numpy.array([])). Note that this trick works even for things where the raw class is not publicly accessible. It's generally better to use the direct reference, but storing the return from type(someobj) for later comparison does have its place.
1 Comment
Not Sure
this is the simplest answer +1