गैर-अवरुद्ध, बहु-थ्रेडेड उदाहरण:
कीबोर्ड इनपुट पर अवरुद्ध होने के बाद से ( input()फंक्शन ब्लॉक) अक्सर ऐसा नहीं होता है कि हम क्या करना चाहते हैं (हम अक्सर अन्य सामान रखना पसंद करेंगे), यहाँ एक बहुत ही अलग-थलग किया हुआ बहु-थ्रेडेड उदाहरण है जो यह बताता है कि आप को कैसे चलाना है। जब भी वे आते हैं, तो कीबोर्ड इनपुट में पढ़ते समय मुख्य अनुप्रयोग ।
यह पृष्ठभूमि में चलने के लिए एक थ्रेड बनाकर काम करता है, लगातार कॉल करता है input()और फिर किसी भी डेटा को एक कतार में भेज देता है।
इस तरह, आपका मुख्य धागा कुछ भी करने के लिए बचा हुआ है, पहले इनपुट से कीबोर्ड इनपुट डेटा प्राप्त करना जब भी कतार में कुछ होता है।
1. नंगे पायथन 3 कोड उदाहरण (कोई टिप्पणी नहीं):
import threading
import queue
import time
def read_kbd_input(inputQueue):
print('Ready for keyboard input:')
while (True):
input_str = input()
inputQueue.put(input_str)
def main():
EXIT_COMMAND = "exit"
inputQueue = queue.Queue()
inputThread = threading.Thread(target=read_kbd_input, args=(inputQueue,), daemon=True)
inputThread.start()
while (True):
if (inputQueue.qsize() > 0):
input_str = inputQueue.get()
print("input_str = {}".format(input_str))
if (input_str == EXIT_COMMAND):
print("Exiting serial terminal.")
break
# Insert your code here to do whatever you want with the input_str.
# The rest of your program goes here.
time.sleep(0.01)
print("End.")
if (__name__ == '__main__'):
main()
2. समान पायथन 3 कोड ऊपर के रूप में, लेकिन व्यापक व्याख्यात्मक टिप्पणियों के साथ:
"""
read_keyboard_input.py
Gabriel Staples
www.ElectricRCAircraftGuy.com
14 Nov. 2018
References:
- https://pyserial.readthedocs.io/en/latest/pyserial_api.html
- *****https://www.tutorialspoint.com/python/python_multithreading.htm
- *****https://en.wikibooks.org/wiki/Python_Programming/Threading
- /programming/1607612/python-how-do-i-make-a-subclass-from-a-superclass
- https://docs.python.org/3/library/queue.html
- https://docs.python.org/3.7/library/threading.html
To install PySerial: `sudo python3 -m pip install pyserial`
To run this program: `python3 this_filename.py`
"""
import threading
import queue
import time
def read_kbd_input(inputQueue):
print('Ready for keyboard input:')
while (True):
# Receive keyboard input from user.
input_str = input()
# Enqueue this input string.
# Note: Lock not required here since we are only calling a single Queue method, not a sequence of them
# which would otherwise need to be treated as one atomic operation.
inputQueue.put(input_str)
def main():
EXIT_COMMAND = "exit" # Command to exit this program
# The following threading lock is required only if you need to enforce atomic access to a chunk of multiple queue
# method calls in a row. Use this if you have such a need, as follows:
# 1. Pass queueLock as an input parameter to whichever function requires it.
# 2. Call queueLock.acquire() to obtain the lock.
# 3. Do your series of queue calls which need to be treated as one big atomic operation, such as calling
# inputQueue.qsize(), followed by inputQueue.put(), for example.
# 4. Call queueLock.release() to release the lock.
# queueLock = threading.Lock()
#Keyboard input queue to pass data from the thread reading the keyboard inputs to the main thread.
inputQueue = queue.Queue()
# Create & start a thread to read keyboard inputs.
# Set daemon to True to auto-kill this thread when all other non-daemonic threads are exited. This is desired since
# this thread has no cleanup to do, which would otherwise require a more graceful approach to clean up then exit.
inputThread = threading.Thread(target=read_kbd_input, args=(inputQueue,), daemon=True)
inputThread.start()
# Main loop
while (True):
# Read keyboard inputs
# Note: if this queue were being read in multiple places we would need to use the queueLock above to ensure
# multi-method-call atomic access. Since this is the only place we are removing from the queue, however, in this
# example program, no locks are required.
if (inputQueue.qsize() > 0):
input_str = inputQueue.get()
print("input_str = {}".format(input_str))
if (input_str == EXIT_COMMAND):
print("Exiting serial terminal.")
break # exit the while loop
# Insert your code here to do whatever you want with the input_str.
# The rest of your program goes here.
# Sleep for a short time to prevent this thread from sucking up all of your CPU resources on your PC.
time.sleep(0.01)
print("End.")
# If you run this Python file directly (ex: via `python3 this_filename.py`), do the following:
if (__name__ == '__main__'):
main()
नमूना उत्पादन:
$ python3 read_keyboard_input.py
कीबोर्ड इनपुट के लिए तैयार:
hey
input_str = hey
hello
input_str = hello
7000
input_str = 7000
exit
input_str = exit
सीरियल टर्मिनल से बाहर निकलें ।
समाप्त।
संदर्भ:
- https://pyserial.readthedocs.io/en/latest/pyserial_api.html
- ***** https://www.tutorialspoint.com/python/python_multithreading.htm
- ***** https://en.wikibooks.org/wiki/Python_Programming/ थ्रेडिंग
- अजगर: मैं सुपरक्लास से उपवर्ग कैसे बनाऊं?
- https://docs.python.org/3/library/queue.html
- https://docs.python.org/3.7/library/threading.html
संबंधित / पार लिंक किया गया:
- PySerial नॉन-ब्लॉकिंग रीड लूप