Strings in Python

The output of the print commands is given below:

Explanation:

$$\begin{matrix} 0 & 1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 & 9 & 10 & 11 \\ \bold P & \bold y &\bold t &\bold h &\bold o &\bold n & \space &\bold W &\bold o &\bold r &\bold l &\bold d \\ -12 & -11 & -10 & -9 & -8 & -7 & -6 & -5 & -4 & -3 & -2 & -1 \\ \end{matrix}$$

name = "Virat Kohli"
father_name = "Prem Kohli"
mother_name = "Saroj Kohli"
class_name = "Class 10"
address = "New Delhi, India"

print("----- PORTFOLIO -----")
print("Name         :", name)
print("Father's Name:", father_name)
print("Mother's Name:", mother_name)
print("Class        :", class_name)
print("Address      :", address)

----- PORTFOLIO -----
Name         : Virat Kohli
Father's Name: Prem Kohli
Mother's Name: Saroj Kohli
Class        : Class 10
Address      : New Delhi, India

Hello
World!
Python	Programming

In the given program, the print() function is used to display output on the screen and escape sequences are used inside strings. The escape sequence \n is used to insert a new line in a string, so after printing Hello, the cursor moves to the next line and World! is printed. The escape sequence \t is used to provide space for one tab, therefore a tab space appears between Python and Programming when it is printed.

Aayan is studying in class X

The endswith() function returns True if the string ends with a particular suffix. Since the string "My classmate is Aayan" ends with "Aayan", the condition becomes true and the first print() statement is executed.

-1
My favorite subject is Python

The find() function returns the index of the first occurrence of the specified value and returns −1 if the value is not found. Since the character 'T' (capital T) is not present in the given string, val becomes -1. As -1 is not greater than 1, the condition in the if statement is false, so the else part is executed.

False

Reason — In Python, a string can be enclosed in single quotes or double quotes.

True

Reason — In a string, each character has a unique index value, and this includes blank spaces, so blank spaces are counted as characters in a string.

False

Reason — A string may consist of letters, digits, or symbols, therefore special characters can be used in strings.

True

Reason — To insert characters that are not allowed in a string, an escape character is used, and backslash (\) is considered as the escape character.

True

Reason — In Python, the * operator is used to repeat a string for a specified number of times, therefore it is called the replication operator in strings.

True

Reason — In Python triple quotes are used to declare a multiline string.

False

Reason — String in Python allows membership operators in and not in.

False

Reason — The escape sequence \t is used to provide space for one tab, not to produce a blank space.

True

Reason — String slicing is used to create a sub string from a string.

False

Reason — The lower() method is used to convert all the characters of a string from uppercase to lowercase.

+

Reason — The concatenation operator + is used for joining multiple strings.

upper()

Reason — The upper() function converts all the characters of the input string into uppercase.

len()

Reason — len() returns the total number of characters in a string (including spaces).

islower()

Reason — The islower() function returns True if the string is in lower case.

el

Reason — In Python, string indexing starts from 0. The slice operator [1:3] returns the characters from index 1 up to index 2 (end index is excluded), therefore the output is el.

2

Reason — The count() function returns the number of occurrences of a character in a string. In the string "Hello How are you", the character "H" appears two times, therefore the output is 2.

isalnum()

Reason — The isalnum() function returns True if all the elements of the string are alphanumeric.

5

Reason — The find() function returns the index of the first occurrence of the specified value. In the given string, the word "studying" starts at index 5, therefore the output is 5.

1. """Hello How are you?
   I am good.""" is an example of Multiline string.
2. The not in operator returns true if a character does not belong to a string.
3. In Python \n is used to introduce a new line.
4. The join function takes an iterator as an input of argument.
5. The isdigit() function returns True if all the elements in the string are digits.

name = "My name is Jack"
new_name = name.upper()
print(new_name)

MY NAME IS JACK

string = "Hello, my friends, I am Jeck"
new_string = string.replace("Jeck", "Tiya")
print(new_string)

Hello, my friends, I am Tiya

string = input("Enter a string: ")
ch = input("Enter a character to find its index: ")
val = string.find(ch)
print("The index of the character is:", val)

Enter a string: Python
Enter a character to find its index: t
The index of the character is: 2

string = "Knowledge is power"
substring = string[0:9]
print(substring)

Knowledge

list1 = ["Riya", "Akshat", "Gem"]
new_string = ",".join(list1)
print(new_string)

Riya,Akshat,Gem

The following are some string operators:

1. Replication operator (*) — The replication operator in Python is used to repeat a string for a specified number of times.

Example:

s1 = "Hello"
print(s1 * 4)

Output: HelloHelloHelloHello

2. Concatenation operator (+) — The concatenation operator (+) is used for joining multiple strings.

Example:

print("Hello" + " Hi")

Output: Hello Hi

3. Membership operator (in) — The membership operator returns true if a character exists in the given string.

Example:

if 't' in "Mountain":
    print("t is present in mountain")

Output: t is present in mountain

4. Membership operator (not in) — This operator returns true if a character does not exist in the given string.

Example:

if 'k' not in "Mountain":
    print("k is not present in mountain")

Output: k is not present in mountain

string1 = input("Enter a string: ")
while True:
    if string1.isalnum():
        print("The given string contains only alphanumeric characters")
        break
    else:
        print("Please enter only alphanumeric characters")
        string1 = input("Enter the string again: ")

Enter a string: Python@123
Please enter only alphanumeric characters
Enter the string again: Python123
The given string contains only alphanumeric characters

string1 = input("Enter a string: ")
if string1.startswith("a"):
    print("It is the first name on the list")
else:
    print("The string does not begin with the letter a")

Enter a string: apple
It is the first name on the list

Enter a string: mango
The string does not begin with the letter a

string1 = input("Enter a string: ")
rev = string1[::-1]

if string1 == rev:
    print("The given string is a palindrome")
else:
    print("The given string is not a palindrome")

Enter a string: madam
The given string is a palindrome

Enter a string: computer
The given string is not a palindrome

string1 = input("Enter a string: ")
rev = string1[::-1]
print("Reversed string is:", rev)

Enter a string: education
Reversed string is: noitacude

string1 = input("Enter a string: ")
unique = ""

for ch in string1:
    if ch not in unique:
        unique = unique + ch

print("Substring with unique characters:", unique)

Enter a string: programming
Substring with unique characters: progamin

def check_password_complexity(password):
    if len(password) < 8:
        return "Weak Password"

    has_upper = False
    has_lower = False
    has_digit = False

    for ch in password:
        if ch.isupper():
            has_upper = True
        elif ch.islower():
            has_lower = True
        elif ch.isdigit():
            has_digit = True

    if has_upper and has_lower and has_digit:
        return "Strong Password"
    else:
        return "Weak Password"

password = input("Enter a password: ")
result = check_password_complexity(password)
print(result)

Enter a password: Abc12345
Strong Password