Ελεγχος#

Εισαγωγή#

Το Control στην Python σάς επιτρέπει να λέτε στο ρομπότ πότε να περιμένει, πότε να επαναλαμβάνει ενέργειες, πώς να λαμβάνει αποφάσεις και πότε να τερματίζει το έργο.

Παρακάτω είναι μια λίστα με όλα τα στοιχεία ελέγχου, συμπεριλαμβανομένων των μεθόδων και των βασικών λέξεων-κλειδιών Python:

  • 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_program – Ends the running program.

  • pass – Placeholder used when no action is needed.

Περιμένετε#

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

Usage:
wait(time, units)

Παράμετροι

Περιγραφή

time

Ο χρόνος αναμονής, ως θετικός ακέραιος αριθμός ή δεκαδικός αριθμός.

units

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

 
# Move right for one second, then stop
robot.move_at(90)
wait(1, SECONDS)
robot.stop_all_movement()

Για#

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.

Χρήση:

for value in expression_list:
    pass

Στοιχεία

Περιγραφή

value

Μια προσωρινή μεταβλητή που αποθηκεύει το τρέχον στοιχείο στην επανάληψη.

expression_list

Η συλλογή στοιχείων που επαναλαμβάνονται (π.χ. λίστα, συμβολοσειρά, εύρος).

 
# Move in a square path.
for index in range(4):
    robot.move_for(50, 0)
    robot.turn_for(RIGHT, 90)


# Print each item in the list
colors = ["Red", "Green", "Blue"]

for color in colors:
    robot.screen.print(color)
    robot.screen.next_row()

Εμφανίζει τρία αντικείμενα που εκτυπώνονται στην οθόνη.

Αν#

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

Χρήση:

if condition:
    pass

Στοιχεία

Περιγραφή

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.

 
# Kick when the screen is pressed
while True:
    if robot.screen.pressing():
        robot.kicker.kick(MEDIUM)
    wait(0.1, SECONDS)

Αν/Αλλιώς#

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

Χρήση:

if condition:
    pass
else:
    pass

Στοιχεία

Περιγραφή

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.

 
# Show one emoji when the screen is pressed,
# and a different emoji when not pressed
while True:
    if robot.screen.pressing():
        robot.screen.show_emoji(EXCITED)

    else:
        robot.screen.show_emoji(BORED)
    
    wait(0.1, SECONDS)

Αν/Ελίφ/Αλλιώς#

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.

Χρήση:

if condition:
    pass
elif condition:
    pass
else:
    pass

Στοιχεία

Περιγραφή

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.

 
# Move the robot forward or reverse
# based on the position of the joystick
def when_axis_changed():
    position = controller.axis1.position()
    if position > 0:
        robot.move_at(0)
    elif position < 0:
        robot.move_at(180)
    else:
        robot.stop_all_movement()

controller.axis1.changed(when_axis_changed)

Ενώ#

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.

Χρήση:

while condition:
    pass

Στοιχεία

Περιγραφή

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.

 
# Keep the LEDs green while the robot is moving
robot.move_for(200, 0, wait=False)
while robot.is_move_active():
    robot.led.on(ALL_LEDS, GREEN)
    wait(50, MSEC)

robot.led.on(ALL_LEDS, BLACK)


while True:
    # Continually flash all LEDs red then green.
    robot.led.on(ALL_LEDS, RED)
    wait(0.5, SECONDS)
    robot.led.on(ALL_LEDS, GREEN)
    wait(0.5, SECONDS)


# Wait until the screen is pressed before
# turning off the LEDs
while not robot.screen.pressing():
    robot.led.on(ALL_LEDS, RED)
    wait(50, MSEC)

robot.led.on(ALL_LEDS, BLACK)

Διακοπή#

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

# Flash LEDs until the screen is pressed
while True:
    robot.led.on(ALL_LEDS, RED)
    wait(0.5, SECONDS)
    robot.led.on(ALL_LEDS, GREEN)
    wait(0.5, SECONDS)

    if robot.screen.pressing():
        break

# Turn the LEDs Off
robot.led.off(ALL_LEDS)

Διακοπή προγράμματος#

stop_program ends a running project.

Usage:
robot.stop_program()

Παράμετροι

Περιγραφή

Αυτή η μέθοδος δεν έχει παραμέτρους.

 
# Stop the project once the screen is pressed
while True:
    robot.led.on(ALL_LEDS, RED)
    wait(0.5, SECONDS)
    robot.led.on(ALL_LEDS, GREEN)
    wait(0.5, SECONDS)
    if robot.screen.pressing():
        robot.stop_program()

Πέρασμα#

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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