Built in Functions

There are many built-in functions in python that can be used to increase the ease of writing code. Let’s discuss a few of them here.

sort()

This function is used to sort the values in data structures such as arrays and lists.

arr = [8,5,1,4,6]
arr.sort()
print('The sorted arr is :',arr)
#prints The sorted arr is [1,4,5,6,8]

find()

Returns the first occurence of the input(pattern) to the find() provided in the given string.

str1 = "Hello World"
index = str1.find("World)"
print(index) #prints 6

len()

len() helps in finding out the size of the given data structure.

arr = [10,5,4,2,3]
print(len(arr)) #prints 5

isdigit()

This function returns true if the string passed as an argument consists of only digits; otherwise it returns false

s = "123";  
print s.isdigit() #prints true

s = "Hello World";
print s.isdigit() #prints false

s = "123Hello"
print s.isdigit() #prints false as it has letters along with digits

reverse()

This function is used to reverse the contents of an array or a list.

arr = [5, 6, 7, 8, 9];
arr.reverse();
print(arr) #prints [9,8,7,6,5]

replace()

This function replaces the first argument passed to the function with the second argument in a given string.

initial_str = "My name is Harry. Harry is a good boy."
final_str = initial_str.replace("Harry", "Potter")
print(final_str) #prints My name is Potter. Potter is a good boy.

append()

This function is used to add a number, character or element of any data type to the end of a list or an array.

arr = [1,2,3,4,5];
arr.append(6);
print(arr) #prints [1,2,3,4,5,6]

arr = ['Harry','Ram',1,2]
arr.append("Jenifer")
print(arr) #prints [Harry,Ram,1,2,Jenifer]

remove()

Removes the first occurence if argument passed for the given object. If you try to remove an element not in list, it would give an exception stating element not in the list.

arr = [1,1,2,3,3]  
arr.remove(1)  
print(arr) #prints 1,2,3,3

arr.remove(4) #gives an exception stating element not in the list

Challenge 1

Create an array namearr

• Initialize it to [1,2,3,4,5]

• Append the number 6 to it and print.

• Reverse arr and print it.

• Sort arr and print it.

• Print length of arr

• Remove the element 6 from arr and print it.

• Print the length of arr,

Expected output

    [1,2,3,4,5,6]
    [6,5,4,3,2,1]
    [1,2,3,4,5,6]
    6
    [1,2,3,4,5]
    5

Challenge 2

-Initialise a string s to “Hello all.Hello people”.

-Find the occurence of the word Hello in the string s and print.

-Replace the word Hello to Hi in s.

-Find if the string s contains only digits and print the verdict.

Expected Output

    0
    Hi all.Hi people.
    False