Consider a module to be the same as a code library. Considers a file containing a set of functions that you want to include in the program.
For, creating a module just save the code with extension .py:-
Example :- Save this code in a file named module_demo.py
print(“Hello, ” + name)
How to use module in program
We can use the module by using the import statement:-
Example : – import the module named module_demo and call the function define inside it.
Array – How to create array and assigning value
Arrays are used to store multiple values in one single variable:
fruits = [“Orange”,”Mango”,”Apple”]
Advantages of Array
Array is a special variable, which can have more than one value at a time or we can say multiple value in single variable.
If you have a list of items (for an example fruit names), storing the fruits in single variables could look like this:
fruits1 = “Orange”
fruits1 = “Mango”
fruits1 = “Apple”
Access the Elements of an Array
We access the element of an array element by its index number.
X = fruits
len() function is use to check the length of an array.
Array Indexing and Slicing
For array indexing python use library called NumPy. On other side slice, a copy of the array is returned but in index array a copy of the original array is returned.
NumPy arrays can be indexed with other arrays or any other sequence with the exception of tuples. The last element is indexed by -1 second last by -2 and so on.
import numpy as np
# create a sequence of integers from 10 to 1 with a step of -1
a = np.arange(10,1,-1)
print(“\n A sequence with negative step : ”,a)
# Indexes are specified by method np.array
newarr = a[np.array([3, 1, 2 ])]
print(“\n Elements at these indices are:\n”,newarr)
Contents of ndarray object can be accessed and modified by indexing or slicing, just like Python’s in-built container objects.
As mentioned earlier, items in array object follows zero-based index. Three different types of indexing methods are available − field access, basic slicing and advanced indexing.
Basic slicing is an extension of Python’s basic concept of slicing to n dimensions. A Python slice object is constructed by giving start, stop, and step parameters to the built-in slice function. This slice object is passed to the array to extract a part of array.
Example : –
Multiple values stored within an array can be accessed at the same time with array slicing. For slicing of an array use colon operator :
when calling the index. The general form is:
<slice> = <array>[start:stop]
Where <slice> is the slice or section of the array object <array>. The index of the slice is specified in [start:stop]. Must Remember that Python counting starts at 0 and ends at n-1. The index [0:3] denoted the first three values out of an array. The index [2:4] tells the third and fourth values out of an array.
An example of slicing the first two elements out of an array is below.
Output : – [2 4 6]