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Thinking Like a Programmer•Interactive notebook lesson•Free

String formatting

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String formatting basics

Codepython

string1 = "This is a apple" # Creating a string

print(string1)

Output

This is a apple

Codepython

fruit = "apple"  # Assigning the string "apple" to the variable 'fruit'

string2 = "This is a {}".format(fruit)  
# The '{}' is replaced with the value of 'fruit' using .format()

print(string2)  # Output: This is a apple

Output

This is a apple

Code

fruit = "apple"  # Assigning the string "apple" to the variable 'fruit'

string2 = f"This is a {fruit}"
# The '{}' is replaced with the value of 'fruit' using f-string formatting

print(string2)  # Output: This is a apple

Codepython

name = "Alice"  # Assigning the string "Alice" to the variable 'name'
age = 25  # Assigning the integer 25 to the variable 'age'

# Using an f-string to format the string dynamically
formatted_string = f"My name is {name} and I am {age} years old."

# Printing the formatted string
print(formatted_string)  # Output: My name is Alice and I am 25 years old.

Output

My name is Alice and I am 25 years old.

Codepython

name = "Bob"  # Assigning the string "Bob" to the variable 'name'
age = 30  # Assigning the integer 30 to the variable 'age'

# Using the .format() method to insert values into the string
formatted_string = "My name is {} and I am {} years old.".format(name, age)

# Printing the formatted string
print(formatted_string)  # Output: My name is Bob and I am 30 years old.

Output

My name is Bob and I am 30 years old.

Codepython

# Assigning values to variables
name = "Bob"  # The person's name
age = 30  # The person's age

# Using the .format() method with positional indexing
# {1} refers to the second argument (name)
# {0} refers to the first argument (age)
formatted_string = "My name is {1} and I am {0} years old.".format(age, name)

# Printing the formatted string
print(formatted_string)  # Output: My name is Bob and I am 30 years old.

Output

My name is Bob and I am 30 years old.

Codepython

# Define a string with placeholders {n} and {a} for dynamic insertion of values
formatted_string = "My name is {n} and I am {a} years old.".format(n=name, a=age)

# The .format() method is used to replace the placeholders with the values of 'name' and 'age'
# 'n' corresponds to the 'name' variable, and 'a' corresponds to the 'age' variable

# Print the resulting formatted string to the console
# The output will be: "My name is <value of name> and I am <value of age> years old."
print(formatted_string)  # Display the final formatted string

Output

My name is Bob and I am 30 years old.

Codepython

# Assign the name and age values to variables
name = "Charlie"
age = 35

# Use old-style string formatting with % operator
# %s is used for inserting a string (name), and %d is used for inserting an integer (age)
formatted_string = "My name is %s and I am %d years old." % (name, age)

# Print the formatted string with the values inserted in place of %s and %d
print(formatted_string)  # Output: "My name is Charlie and I am 35 years old."

Output

My name is Charlie and I am 35 years old.

Codepython

# Define a list of words
words = ["Hello", "World"]

# Use the .join() method to concatenate the elements of the list with a space (" ") between them
# The .join() method joins each element of the list into a single string
sentence = " ".join(words)

# Print the concatenated sentence
# The result will be: "Hello World"
print(sentence)

Output

Hello World

Codepython

# Assign the value of pi
pi = 3.1415926535

# Use f-string formatting to round pi to 2 decimal places
# The syntax {pi:.2f} means format the value of 'pi' with 2 decimal places
print(f"Pi rounded to 2 decimals: {pi:.2f}")  

# Use .format() method to round pi to 3 decimal places
# The syntax {:.3f} means format the value of 'pi' with 3 decimal places
print("Pi rounded to 3 decimals: {:.3f}".format(pi))

Output

Pi rounded to 2 decimals: 3.14
Pi rounded to 3 decimals: 3.142

String formatting basics

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