<evaluates — title: Control | VEX GO - Python API description: Explore the Python API reference for controls with VEX GO. Find detailed descriptions for methods, parameters, and usage examples.

Control

Introduction

Control includes methods for timing, program flow, conditional logic, and project termination. These controls let you pause execution, create loops, define logic paths, and end a program.

Below is a list of available controls, including methods and core Python keywords:

• wait – Pauses execution for a given number of milliseconds or seconds.

• for – Repeats code for each item in a sequence.

• if – Executes code if a condition is true.

• if/else – Runs different code depending on a condition.

• if/elif/else – Checks multiple conditions in order.

• while – Repeats code while a condition is true.

• break – Exits a loop immediately.

• stop_program – Ends the running program.

• pass – Placeholder used when no action is needed.

wait

wait pauses for a specific amount of time before moving to the next line of code.

Usage:
wait(time, units)

Parameters	Description
time	The amount of time to wait, as a positive integer or float.
units	The unit that represents the wait time: MSEC (default) – milliseconds SECONDS

# Build Used: Super Code Base 2.0
def main():
    # Turn right for one second
    drivetrain.turn(RIGHT)
    wait(1, SECONDS)
    drivetrain.stop()

# Start threads — Do not delete
start_thread(main)

for

for iterates over a sequence (such as a list, tuple, dictionary, set, or string) or any iterable object. It executes the block of code once for each item in the sequence.

Usage:

for value in expression_list:
    pass

Components	Description
value	A temporary variable that stores the current element in the iteration.
expression_list	The collection of elements being looped through (e.g., list, string, range).

# Build Used: Super Code Base 2.0
def main():
    # Move in a square path
    for index in range(4):
        drivetrain.drive_for(FORWARD, 100, MM)
        drivetrain.turn_for(RIGHT, 90)

# Start threads — Do not delete
start_thread(main)

if

if executes the indented block of code if the condition evaluates to True.

Usage:

if condition:
    pass

Components	Description
condition	An expression or variable that is evaluated when the statement runs. If it evaluates to True, the code inside the if block executes; if it evaluates to False, the block is skipped.

# Build Used: Super Code Base 2.0
def main():
    # Turn when the bumper is pressed
    while True:
        if bumper.is_pressed():
            drivetrain.turn_for(RIGHT, 90)
        wait(0.1, SECONDS)

# Start threads — Do not delete
start_thread(main)

if/else

if and else determine which indented block of code runs based on whether the condition evaluates to True or False.

Usage:

if condition:
    pass
else:
    pass

Components	Description
condition	An expression or variable that is evaluated when the statement runs. If it evaluates to True, the code inside the if block executes; if it evaluates to False, the code inside the else block executes instead.

# Build Used: Super Code Base 2.0
def main():
    # Turn when the bumper is pressed
    while True:
        if bumper.is_pressed():
            drivetrain.turn(RIGHT)
        else:
            drivetrain.stop()
        wait(0.1, SECONDS)

# Start threads — Do not delete
start_thread(main)

if/elif/else

The if/elif/else structure selects which indented block of code runs based on conditions:

• if runs its block if the condition evaluates to True.

• elif checks additional conditions only if all previous conditions evaluated as False. Multiple elif statements can be used.

• else runs its block only if none of the previous conditions evaluated as True.

Usage:

if condition:
    pass
elif condition:
    pass
else:
    pass

Components	Description
condition	An expression or variable that is evaluated when the statement runs. The first condition that evaluates to True determines which block executes; if none are True, the else block runs.

# Build Used: Super Code Base 2.0
def main():
    # Change the LED while turning
    drivetrain.turn(RIGHT)
    while True:
        if drivetrain.get_heading() < 120:
            bumper.set_color(OFF)
        elif drivetrain.get_heading() < 240:
            bumper.set_color(RED)
        else:
            bumper.set_color(GREEN)
        wait(0.2, SECONDS)

# Start threads — Do not delete
start_thread(main)

while

while repeatedly runs methods as long as the condition is True. It can also be used like a “wait until” by adding not to the condition, as shown in the example below.

Usage:

while condition:
    pass

Components	Description
condition	An expression or variable that is evaluated before each iteration. If it evaluates to True, the loop continues; if it evaluates to False, the loop stops.

# Build Used: Super Code Base 2.0
def main():
    # Turn when the bumper is pressed
    while True:
        if bumper.is_pressed():
            drivetrain.turn(RIGHT)
        else:
            drivetrain.stop()
        wait(0.1, SECONDS)

# Start threads — Do not delete
start_thread(main)

# Build Used: Super Code Base 2.0
def main():
    # Turn the other direction when the bumper is pressed
    drivetrain.turn(LEFT)
    while not bumper.is_pressed():
        wait(0.2, SECONDS)
    drivetrain.turn(RIGHT)

# Start threads — Do not delete
start_thread(main)

break

break exits a loop immediately.

Usage:

break

Parameters	Description
	This keyword has no parameters.

# Build Used: Super Code Base 2.0
def main():
    # Stop turning after pressing the bumper
    while True:
        drivetrain.turn(RIGHT)
        if bumper.is_pressed():
            break
        wait(0.2, SECONDS)
    drivetrain.stop()
    bumper.set_color(RED)

# Start threads — Do not delete
start_thread(main)

stop_program

stop_program ends a running project.

Usage:
stop_program()

Parameters	Description
	This method has no parameters.

# Build Used: Super Code Base 2.0
def main():
    # Stop the project after pressing the bumper
    while True:
        drivetrain.turn(RIGHT)
        if bumper.is_pressed():
            break
        wait(0.2, SECONDS)
    stop_program()

# Start threads — Do not delete
start_thread(main)

pass

pass is a placeholder for future code and can be used to avoid errors in empty loops, conditionals, and functions.

Usage:

pass

Parameters	Description
	This keyword has no parameters.

if condition:
    pass

def function():
    pass