Basic Input output operations

 1.3          Basic Input output operations

Python provides simple and intuitive ways to handle input and output (I/O) operations. These operations are essential for interacting with the user or handling data.

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1. Input Operations

The input() function is used to get input from the user. By default, it returns the input as a string.

Syntax:

input(prompt)

Example:

name = input("Enter your name: ")

print(f"Hello, {name}!")

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print('Enter your name:')
x = input()
print('Hello, ' + x)

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# Taking input as string

x = input('Enter your name:')
print('Hello, ' + x)

Converting Input to Other Data Types:

Since input() returns a string, you often need to convert the input to another type:

# Taking input as int

# Typecasting to int

age = int(input("Enter your age: "))

# Typecasting to float

height = float(input("Enter your height: "))

print(f"You are {age} years old and {height} meters tall.")

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Example : Taking two integers from users and adding them.

# Taking number 1 from user as int
num1 = int(input("Please Enter First Number: "))

# Taking number 2 from user as int
num2 = int(input("Please Enter Second Number: "))

# adding num1 and num2 and storing them in
# variable addition
addition = num1 + num2

# printing
print("The sum of the two given numbers is {} ".format(addition))

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Example : Taking Two lists as input and appending them
# Taking list1 input from user as list
list1 = list(input("Please Enter Elements of list1: "))

# Taking list2 input from user as list
list2 = list(input("Please Enter Elements of list2: "))


# appending list2 into list1 using .append function
for i in list2:
    list1.append(i)

# printing list1
print(list1)

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2. Output Operations

The print() function is used to display output to the console.

Syntax:

print(*objects, sep=' ', end='\n', file=sys.stdout, flush=False)

• *objects: One or more objects to be printed.
• sep: Separator between objects (default is a space).
• En//;d: What to print at the end of the output (default is a newline).
• file: Target output stream (default is sys.stdout).
• flush: If True, forces the output to be flushed immediately.

Example:

print("Hello, World!")  # Prints Hello, World!

print("Python", "is", "fun", sep="-")  # Python-is-fun

print("This is the first line.", end=" ")

print("This is the same line.")

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3. String Formatting in Output

a. Using f-strings (Python 3.6+)

name = "Alice"

age = 25

print(f"My name is {name} and I am {age} years old.")

b. Using .format() Method

print("My name is {} and I am {} years old.".format(name, age))

c. Using %-Formatting (Old Style)

print("My name is %s and I am %d years old." % (name, age))

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4. Reading and Writing Files

a. Reading a File

with open("example.txt", "r") as file:

    content = file.read()

    print(content)

b. Writing to a File

with open("example.txt", "w") as file:

    file.write("Hello, Python!")

c. Appending to a File

with open("example.txt", "a") as file:

    file.write("\nAppended text.")

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5. Example: Basic Input and Output Program

# A simple program to calculate the square of a number

number = float(input("Enter a number: "))

square = number ** 2

print(f"The square of {number} is {square}.")

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Key Points to Remember

1.    Input: Always comes in as a string, so convert it to the desired data type if necessary.

2.    Output: Use print() with optional formatting for better presentation.

3.    Files: Handle files using with to ensure proper closing of resources.