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Learning Numpy - Simple Tutorial For Beginners - NumPy - Ndarray Object Part 2

Learning Numpy - Simple Tutorial For Beginners - NumPy - Ndarray Object Part 2

What Is Ndarray Object?

The most important object defined in NumPy is an N-dimensional array type called ndarray. It describes the collection of items of the same type. Items in the collection can be accessed using a zero-based index.

Every item in an ndarray takes the same size of block in the memory. Each element in ndarray is an object of data-type object (called dtype).

Any item extracted from ndarray object (by slicing) is represented by a Python object of one of array scalar types. The following diagram shows a relationship between ndarray, data type object (dtype) and array scalar type −

An instance of ndarray class can be constructed by different array creation routines described later in the tutorial. The basic ndarray is created using an array function in NumPy as follows −

numpy.array

It creates an ndarray from any object exposing array interface, or from any method that returns an

array.numpy.array(object, dtype = None, copy = True, order = None, subok = False, ndmin = 0)
Sr.No. Parameter & Description
1 object: Any object exposing the array interface method returns an array, or any (nested) sequence.
2 dtype: Desired data type of array, optional
3 copy: Optional. By default (true), the object is copied
4 order: C (row major) or F (column major) or A (any) (default)
5 subok: By default, returned array forced to be a base class array. If true, sub-classes passed through
6 ndmin: Specifies minimum dimensions of resultant array

Example 1

In [5]:
import numpy as np
a = np.array([1,2,3])
print (a)
[1 2 3]

Example 2

In [6]:
# more than one dimensions 
import numpy as np
a = np.array([[1, 2], [3, 4]])
print (a)
[[1 2]
 [3 4]]

Example 3

In [7]:
# minimum dimensions 
import numpy as np
a = np.array([1, 2, 3,4,5], ndmin = 2)
print (a)
[[1 2 3 4 5]]

The ndarray object consists of contiguous one-dimensional segment of computer memory, combined with an indexing scheme that maps each item to a location in the memory block.



Dolly Solanki  Dolly Solanki