3.11 Basics of NumPy arrays

-

 v  Basics of NumPy arrays: -

Ø The basics of NumPy arrays consist of manipulating arrays to access the data and sub arrays, to split, reshape and join arrays.

Ø The basic array manipulations are

1.      Attributes of arrays.

2.      Slicing and indexing of arrays.

3.      Reshaping of arrays.

4.      Joining and splitting of arrays.

 

1)    Attributes of arrays: -

Ø The attributes of an array determine the size, shape, memory consumption and data types of an array.

Ø Each array has attributes like ndim (no of dimensions), shape (size of each dimension), and size (total size of array).

Ø N-dimensional array (ndarray) is most important object defined in NumPy.

Ø ndarray is a fixed size multi-dimensional container of elements of same type and size.

Ø Ndarray attributes are:

a.      ndarray.ndim

b.      ndarray.shape

c.      ndarray.size

d.      ndarray.itemsize

a)     ndarray.ndim: -

Ø  This array attribute returns the number of array dimensions.

Ø  In NumPy, the number of dimensions is referred to as Rank.

Ø  We get the dimension of array using ndim attribute.

Example: -

Output: -


b)     ndarray.shape: -

This array attribute returns tuple describing the length of each dimension.

We use shape attribute to get the number of elements in the row.

Example: -

Output: -


c)     ndarray.size: -

Ø  The array size attribute returns the total number of elements in the array.

 

Example: -

Output: -


d)     ndarray.itemsize: -

Ø  The attribute itemsize returns the memory size (in bytes) of elements in the array.

 

Example: -

Output: -


2)    Slicing and indexing of arrays: -

Ø Slicing means accessing a range of elements from an array.

Ø The syntax is similar to Python lists.

 

 


·        Start: - The starting index. If omitted, defaults to 0th position.

·        End: - The ending index. (not including value at this index).

·        Step size: - The spacing between index values, default is 1.

Ø Indexing means accessing individual elements of an array using their position (index).

Ø Indexing starts from 0 (like normal Python lists).

Ø In multi-dimensional arrays, you use comma-separated indices.

 

Example: -


Output: -


3)    Reshaping of arrays: -

Ø The reshape( ) function gives a new shape to an array without changing the data.

Ø This function takes a single argument that specifies the new shape of the array.

 

Example: -

Output: -


4)    Joining and splitting of arrays: -

Ø Array joining means combining two or more arrays into a single array.

Ø The concatenate( ) function can join two or more arrays into a single array.

 

Example: -

Output: -


Ø  Array splitting means to split a single array into multiple arrays.

Ø  We use array_split( ) for splitting an array.

Example: -


Output: -



Popular posts from this blog

operators in c programming

-
Image
v Operators: - An operator is a symbol that tells or intimates to the compiler to perform specific calculations or manipulations on one or more operands. Operators are essential for performing computations and making decisions in programs.   a + b is an operation a & b are operands + is an operator   Based on number of operands involved: 1.      Unary operators: - unary operators can be applied on only one operator. Example: -   ++ , -- , - (unary minus) , sizeof , ~ (compliment) , ! (not).   2.      Binary operators: - binary operators can be applied on two operands. Example: -   + , -,   * , / , etc.   3.    Ternary operators: - Ternary operator can be applied on three operands. Example: -   ?: (ternary conditional operator).   C supports several operators, can be classified into following...
Read more

Variables in c

-
Image
  Variables: - A variable is a data name or an identifier which stores a value that can be changed during the program execution.  Every variable might belong to any of the data types, like int, float, char, etc.  The name of a variable can be composed of letters, digits, and the underscore character. It must begin with either a letter or an underscore.  Variables are case-sensitive because uppercase and lowercase letters are distinct. C programming language also allows defining various other types of variables, like numeric array, character array, pointer, Structure, Union, Enumeration and etc.               Example: - sum, height, _value Declaring a variable in C: - Variable declaration means telling the compiler about the name and type of a variable before using it in the program. Variable declaration is the process of reserving a memory location and defining the type of data that will be stored in that locatio...
Read more

2.4 Arrays in c programming

-
Image
  Arrays: - An array is a collection of elements of the same data type stored in contiguous memory locations. It is a derived data type and a homogenous data structure. It is a variable which can store multiple values of the same type under a single variable name, making it easier to manage and manipulate related data. The size of an array is fixed. To access the elements of an array, we use indexes or subscripts accordingly. array index or subscript is used to identify array elements address. Array index or subscript starts with 0 to n-1.   Declaration of an array: - The declaration of an array means telling the compiler to create an array variable and reserving memory for a fixed number of elements of the same data type. Initialization of an array: - Initializing an array means assigning initial values to its elements. Types of arrays: - Arrays are classified based on the number of dimensions they have:             ...
Read more