控制#

介绍#

Python 中的控制功能可以让你告诉机器人何时等待、何时重复操作、如何做出决定以及何时结束项目。

以下是可用控件列表，包括方法和核心 Python 关键字：

  • wait – Pauses the project for a given time.

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

  • if – Runs 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_project – Ends the running project.

  • pass – Placeholder used when no action is needed.

等待#

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

Usage:
wait(time, units)

参数

描述

time

等待时间，以正整数或小数表示。

units

The unit that represents the wait time: MSEC (default) – milliseconds, or SECONDS

 
def main():
    # Turn right for one second, then stop
    drivetrain.turn(RIGHT)
    wait(1, SECONDS)
    drivetrain.stop()

# VR threads — Do not delete
vr_thread(main)

为了#

for repeats a set of actions a specific number of times. for can be used to loop through items in lists, tuples, dictionaries, sets, strings, or for a specified amount of loops with range.

使用次数：

for value in expression_list:
    pass

成分

描述

value

一个临时变量，用于存储迭代中的当前元素。

expression_list

循环遍历的元素集合（例如，列表、字符串、范围）。

 
def main():
    # Move in a square path
    for index in range(4):
        drivetrain.drive_for(FORWARD, 100, MM)
        drivetrain.turn_for(RIGHT, 90, DEGREES)

# VR threads — Do not delete
vr_thread(main)


def main():
    # Print each item in the list
    colors = ["Red", "Green", "Blue"]

    for color in colors:
        brain.print(color)
        brain.new_line()

# VR threads — Do not delete
vr_thread(main)

如果#

if runs the indented block of code if the condition is True.

用法：

if condition:
    pass

成分

描述

condition

An expression or variable that is checked when the statement runs. If it is True, the code inside the if block executes; if it is False, the block is skipped.

 
def main():
    # Turn right until facing south
    while True:
        if drivetrain.heading(DEGREES) < 180:
            drivetrain.turn_for(RIGHT, 90, DEGREES)
        wait(0.1, SECONDS)

# VR threads — Do not delete
vr_thread(main)

如果/否则#

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

用法：

if condition:
    pass
else:
    pass

成分

描述

condition

An expression or variable that is checked when the statement runs. If it is True, the code inside the if block executes; if it is False, the code inside the else block executes instead.

 
def main():
    # Drive after turning around
    while True:
        if drivetrain.rotation(DEGREES) < 180:
            drivetrain.turn_for(RIGHT, 90, DEGREES)
        else:
            drivetrain.drive(FORWARD)
        wait(0.1, SECONDS)

# VR threads — Do not delete
vr_thread(main)

如果/否则#

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

  • if runs its block if the condition is True.

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

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

用法：

if condition:
    pass
elif condition:
    pass
else:
    pass

成分

描述

condition

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

 
def main():
    # Move depending on the detected color
    while True:
        if front_eye.detect(RED):
            drivetrain.drive(FORWARD)
        elif front_eye.detect(GREEN):
            drivetrain.drive(REVERSE)
        else:
            drivetrain.turn(RIGHT)
        wait(0.1, SECONDS)

# VR threads — Do not delete
vr_thread(main)

尽管#

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

用法：

while condition:
    pass

成分

描述

condition

An expression or variable that is checked before each iteration. If it is True, the loop continues; if it is False, the loop stops.

 
def main():
    while True:
        # Move in a square path forever
        drivetrain.drive_for(FORWARD, 150, MM)
        drivetrain.turn_for(RIGHT, 90, DEGREES)

# VR threads — Do not delete
vr_thread(main)


def main():
    # Wait until an object is detected to stop driving
    drivetrain.drive(FORWARD)
    while not front_distance.found_object():
        wait(50, MSEC)
    drivetrain.stop()

# VR threads — Do not delete
vr_thread(main)

休息#

break exits a loop immediately. break can be used to leave loops that otherwise would loop forever.

def main():
    # Stop turning after a button is pressed
    while True:
        drivetrain.turn(RIGHT)
        if front_distance.found_object():
            break
    drivetrain.stop()

# VR threads — Do not delete
vr_thread(main)

停止项目#

stop_project ends a running project.

Usage:
stop_project()

参数

描述

此方法没有参数。

 
def main():
    # Stop the project after a button is pressed
    while True:
        drivetrain.turn(RIGHT)
        if front_distance.found_object():
            stop_program()
        drivetrain.drive(FORWARD)

# VR threads — Do not delete
vr_thread(main)

经过#

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

if condition:
    pass


def function():
    pass
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