String Formatting#

Introduction#

f-strings are the recommended way to format text and numbers in Python. They allow variables, expressions, and function calls to be embedded directly inside {}.

To create an f-string, add f before the string, and place any variable, expression, or function call inside {}.

f-Strings – Embed variables and expressions directly in text.

  • f"{value}" – Displays variables, expressions, or function calls inside a string.

Formatting Numbers in f-strings – Control how numeric values appear.

  • :.xf – Sets the number of decimal places to show.

  • round – Rounds a number to a given number of decimal places.

  • :, – Adds commas as thousands separators.

  • :.x% – Converts a decimal to a percentage with x decimal places.

  • :#x – Formats a number as hexadecimal.

  • :b – Formats a number as binary.

String Combination – Combine text and values.

  • f"{value}" – Combine strings and variables in a single expression.

  • + operator – Concatenate strings manually with optional type conversion.

String Methods – Change the case of text.

  • upper() – Converts all characters to uppercase.

  • lower() – Converts all characters to lowercase.

Substring Checks – Test for presence or position of text.

  • in – Checks if a word exists in a string.

  • startswith() – Checks if a string begins with a given value.

  • endswith() – Checks if a string ends with a given value.

Escape Sequences – Format output with special characters.

  • \n – Adds a line break (new line).

  • \t – Adds a tab space between items.

Formatting Numbers in f-strings#

f-strings allow precise control over decimal places, rounding, thousands separators, and more by using the following format specifiers:

Fixed Decimal Places#

.xf controls how many decimal places a number is displayed with.

Usage:
.xf

Parameters

Description

x

The amount of decimal places to show.

# Example coming soon

Rounding Numbers#

round rounds numbers outside of an f-string or inside of the {}.

Usage:
round(number, x)

Parameters

Description

number

The number to round.

x

The amount of decimal places to round to.

# Example coming soon

Thousands Separator#

, inserts commas as thousands separators to make large numbers more readable.

Usage:
,

Parameters

Description

This format specifier has no parameters.

# Example coming soon

Percentage#

.x% formats decimal values as percentages.

Usage:
.x%

Parameters

Description

x

The amount of decimal places to show.

# Example coming soon

Hexadecimal#

.#x converts numbers to hexadecimal.

Usage:
.#x

Parameters

Description

This format specifier has no parameters.

# Example coming soon

Binary#

b converts numbers to binary (base 2).

Usage:
b

Parameters

Description

This format specifier has no parameters.

# Example coming soon

Combining Strings#

You can combine (or concatenate) strings using two approaches:

Using f-strings#

With f-strings, you can embed variables directly inside {}.

# Example coming soon

+ Operator#

You can combine strings manually using the + operator.

Note: Non-strings must first be converted to strings using str().

# Example coming soon

String Methods#

Python provides built-in methods for modifying and checking strings.

upper#

upper converts all letters in a string to uppercase.

Usage:
upper()

Parameters

Description

This method has no parameters.

# Example coming soon

lower#

lower converts all letters in a string to lowercase.

Usage:
lower()

Parameters

Description

This method has no parameters.

# Example coming soon

Checking for Substrings#

in#

in is a keyword that checks if a word exists in a string.

# Example coming soon

startswith#

startswith returns if a string starts with a specific word. This method returns a Boolean value:

  • True - The word starts the string.

  • False - The word does not start the string.

Usage:
startswith(substring)

Parameters

Description

substring

The substring to check inside the string.

# Example coming soon

endswith#

endswith returns if a string ends with a specific word. This method returns a Boolean value:

  • True - The word ends the string.

  • False - The word does not end the string.

Usage:
startswith(substring)

Parameters

Description

substring

The substring to check inside the string.

# Example coming soon

Escape Sequences#

Escape sequences are special characters used inside strings to format text output. They are only available for use with the Console.

New Line#

\n moves text to a new line when printing.

# Display text on two lines
print("First line\nSecond line")

Tab Spacing#

\t inserts a tab space between words or numbers,

# Display the quantity of barrels
quantity = 2
print("Barrels:\t", quantity)