What is TypeError: only integer scalar arrays can be converted to a scalar index?

By | November 3, 2020

Recently, there are some people who reported that they get the TypeError: only integer scalar arrays can be converted to a scalar index issue. By the way, what is it? And how to fix the error? Let us find out that information here.

About the error

Now, we are going to share some examples and solutions of the error. We get information that the TypeError: only integer scalar arrays can be converted to a scalar index issue may occur when you try to use a list of integers in a numpy array or when you are missing in concatenate.

TypeError only integer scalar arrays can be converted to a scalar index issue

Example 1:

The TypeError: only integer scalar arrays can be converted to a scalar index issue is occur when you try to use a list of integers in a numpy array.

We get information that the code below can be cause the error of TypeError: only integer scalar arrays can be converted to a scalar index.

The code:

x = list(range(0,10))

random.shuffle(x)

ind = np.argsort(x)

x[ind]

For note that the problem is different than in the state, Numpy array TypeError: only integer scalar arrays can be converted to a scalar index”, which is trying something more complex. This mistake in this example is that you are trying to use a list of indexes on an ordinary python list. You may expect it happens much more amply than only with using range and shuffle.

Solution of example 1:

The problem is that you are trying to index x (an ordinary Python list). You may think that it was a Numpy array. To solve the error, simply you are able to convert x to a numpy array:

x = list (range (0,10))

random.shuffle (x)

ind = np.argsort (x)

x = np.array (x)

x [ind]

Example 2:

You are concatenating 2 one dimensional Numpy arrays. Then, you get the error. What is wrong in your code?

import numpy

a = numpy.array ([1, 2, 3])

b = numpy.array ([5, 6])

numpy.concatenate(a, b)

Traceback (most recent call last):

File “<stdin>”, line 1, in <module>

The code above produces the error.

Solution of example 2:

Apparently, you are missing [] in concatenate(). To fix it, you have to see the modified code.

import numpy

a = numpy.array ([1, 2, 3])

b = numpy.array ([5, 6])

numpy.concatenate ([a, b])

array ([1, 2, 3, 5, 6])

Scalars in Python

You have to know that Python assigns only one type of a particular data class. There is only one integer type; floating-point type. This is able to be convenient in applications that do not require to be concerned with all the ways data can be represented in a computer. But, for scientific computing, more control is often required.

Based on the research, In NumPy, there are 24 new fundamental Python types to explain different types of scalars. Those type are based on the types available in the C language which CPython is written in with some additional types compatible with the types of Python.

For your information, Array scalars have the same attributes and ways as ndarrays. This lets one to deal the items of array on the same footing as arrays. It is smoothing out rough edges which result when you are mixing scalar and array operations. Besides, array scalars live in a hierarchy of data types. They are able to be detected by using the hierarchy. For instance, isinstance(val, np.generic) will be able to return True if val is an array scalar object. In alternative, what type of array scalar is come will be able to be specified by using other members of the data type hierarchy. So, for instance, (val, np.complexfloating) will be able to return true if val is a complex value.

Create Numpy Arrays

A Numpy library is the array object/ the ndarray object. You are going to use Numpy arrays to do logical, statistical, and Fourier transforms. As part of working with Numpy, one of the first things you can do is make Numpy arrays. In this section, we are going to inform you a data professional about the different tools available to make Numpy arrays.

Apparently, There are three different methods to make Numpy arrays:

  1. Using Numpy functions.
  2. Conversion from other Python structures like the lists.
  3. Using special library functions.

Using Numpy functions

Numpy has built-in functions for making arrays. Now, we are going to some of them in this guide.

First, let us make a one-dimensional array or an array with a rank 1. Arange is a widely used function to make an array quickly. Passing a value 20 to the arange function makes an array with values ranging from 0 to 19. To verify the dimensionality of this array, you need to use the shape property. Since there is no value after the comma, this is a one-dimensional array. To access a value in this array, you are able to specify a non-negative index. As in other programming languages, the index starts from zero. Therefore to access the fourth element in the array, you have to use the index 3.

Numpy Arrays are mutable. It means that you are able to change the value of an element in the array after an array has been initialized. Please use the print function to view the contents of the array. Therefore, if you try to assign a string value to an element in an array, whose data type is int, you will be able to get an error.

Now, let us talk about making a two-dimensional array. If you only use the arange function, it will be able to output a one-dimensional array. To make it a two-dimensional array, make sure that its output with the reshape function. 20 integers will be made and then it will be able to convert the array into a two-dimensional array with four rows and five columns. Check the dimensionality of this array. Since you get two values, this is a two-dimensional array. To access an element in a two-dimensional array, you have to specify an index for both the row and the column.

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