String Formatting#

Introduction #

The .format() method in Python is used to create strings that include variables, expressions, or values. This method replaces curly brace placeholders {} in a string with values provided inside .format().

x = 1
y = 5

# Display the variables using .format()
brain.screen.print("Position: ({}, {})".format(x, y))

# Display a calculation using .format()
brain.screen.print("Sum: {}".format(5 + 3))

# Display the robot's battery capacity using .format()
brain.screen.print("Battery: {}%".format(brain.battery.capacity()))

Formatting Numbers with .format – Insert values and expressions into a string.

:.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.

Colors – Change the color of text in the Console

Colors – Set the text color of the Console.

Combining Strings – Combine text and values.

.format() – 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.

Checking for Substrings – 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 with `.format`#

.format can be used to control how numbers appear, including decimal places, rounding, and other formatting styles such as:

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.

# Display pi with 2 decimal places
pi = 3.1415926535
brain.screen.print("Pi: {:.2f}".format(pi))
# Output: Pi: 3.14

Rounding Numbers #

round rounds a number to a specific number of decimal places before formatting.

Usage:
round(number, x)

Parameters	Description
`number`	The number to round.
`x`	The amount of decimal places to round to.

# Display a value rounded to only 2 decimal places
value = 5.6789
brain.screen.print("Rounded: {}".format(round(value, 2)))
# Output: Rounded: 5.68

Thousands Separator #

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

Usage:
:,

Parameters	Description
	This format specifier has no parameters.

# Display a large number separated with commas
number = 1234567
brain.screen.print("Formatted: ")
brain.screen.next_row()
brain.screen.print("{:,}".format(number))
# Output: Formatted: 1,234,567

Percentage #

:.x% formats decimal values as percentages.

Usage:
:.x%

Parameters	Description
`x`	The amount of decimal places to show.

# Display a converted decimal to a percentage
value = 0.875
brain.screen.print("Score: {:.1%}".format(value))
# Output: Score: 87.5%

Hexadecimal #

:#x converts numbers to hexadecimal.

Usage:
:#x

Parameters	Description
	This format specifier has no parameters.

# Convert 255 to hexadecimal
number = 255
brain.screen.print("Hex: {:#x}".format(number))
# Output: Hex: 0xff

Binary #

:b converts numbers to binary (base 2).

Usage:
:b

Parameters	Description
	This format specifier has no parameters.

# Convert 3 to binary
brain.screen.print("Binary: {:b}".format(3))
# Output: Binary: 11

Colors #

You can change what color the text will be when printing to the Print Console by using the following color codes:

[31m – Red
[32m – Green
[34m – Blue
[30m – Black
[37m – White
[33m – Yellow
[91m – Orange
[35m – Purple
[36m – Cyan
[97m – Transparent

All color codes need to follow an escape sequence = \033 in order to function.

You can use this directly in a print command with a string.

# Print VEXcode in Red to the Print Console
print("\033[31mVEXcode")

You can also use it on its own to set all print commands afterwards to the set color.

# Set the Print Console text color to Red before printing
print("\033[31m")
print("VEXcode")

Combining Strings #

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

Using `.format`#

Insert values directly into the string using {}.

# Display an answer based on the given emotion
emotion = "good"
brain.screen.print("I'm {}, you?".format(emotion))

+ Operator #

Join multiple parts by using +.

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

# Display the x and y values
x = 10
y = 20
brain.screen.print("X: " + str(x) + ", Y: " + str(y))

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.

message = "vexcode"
brain.screen.print(message.upper())  # Output: VEXCODE

lower #

lower converts all letters in a string to lowercase.

Usage:
lower()

Parameters	Description
	This method has no parameters.

message = "VEXCODE"
brain.screen.print(message.lower())  # Output: vexcode

Checking for Substrings #

in #

in is a keyword that returns a Boolean indicating whether a word exists in a string.

True - The word exists in the string.
False - The word does not exist in the string.

message = "Hey everyone!"
if "Hey" in message:
    brain.screen.print("Hello!")

startswith #

startswith returns a Boolean indicating whether a string begins with a given 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.

message = "AIM Robot"

if message.startswith("AIM"):
    brain.screen.print("AIM first!")

endswith #

endswith returns a Boolean indicating whether a string ends with a given 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.

message = "AIM Robot"

if message.endswith("Robot"):
    brain.screen.print("Robot last!")

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)