我想用Python从键盘读取数据。我尝试了这段代码：
nb = input('Choose a number')
print('Number%s \n' % (nb))
但是它不起作用，无论是在 Eclipse 还是在终端中，它总是停止问题。我可以输入一个数字，但什么也没发生。
你知道为什么吗？
使用
input('Enter your input:')
如果您使用Python 3。
如果你想要一个数值，只需转换它：
try:
mode = int(input('Input:'))
except ValueError:
print("Not a number")
如果您使用Python 2，则需要使用
raw_inputinput您似乎在这里混合了不同的Python（Python 2.x 与 Python 3.x）... 这基本上是正确的：
nb = input('Choose a number: ')
问题是它仅在Python 3中受支持。正如@sharpner回答的那样，对于旧版本的Python（2.x），您必须使用该函数
raw_inputnb = raw_input('Choose a number: ')
如果您想将其转换为数字，那么您应该尝试：
number = int(nb)
...尽管您需要考虑到这可能会引发异常：
try:
number = int(nb)
except ValueError:
print("Invalid number")
如果您想使用格式打印数字，建议在 Python 3
str.format()print("Number: {0}\n".format(number))
代替：
print('Number %s \n' % (nb))
但这两个选项（
str.format()%由于阻止键盘输入（因为
input()（搜索代码
input()）。
其工作原理是创建一个在后台运行的线程，不断调用
input()，然后将其接收到的任何数据传递到队列。这样，你的主线程就可以做任何它想做的事情，只要队列中有东西，就从第一个线程接收键盘输入数据。
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()
"""
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
- https://stackoverflow.com/questions/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()
结束。
$ python3 read_keyboard_input.py
准备键盘输入：
嘿
输入_str = 嘿
你好
输入_str = 你好
7000
输入字符串 = 7000
退出
输入_str = 退出
退出串行终端。
注意
Queue.put()和
Queue.get()以及其他Queue类方法都是线程安全的！ （这与 C++ 标准模板库中的队列和其他容器不同！）由于 Python Queue 类及其方法是线程安全的，这意味着它们实现了线程间操作所需的所有内部锁定语义，因此每个队列类中的函数调用可以被视为单个原子操作。请参阅文档顶部的注释：https://docs.python.org/3/library/queue.html（已添加重点）：
队列模块实现了多生产者、多消费者队列。参考资料：当必须在多个线程之间安全地交换信息时，它在线程编程中特别有用。此模块中的 Queue 类实现了所有必需的锁定语义。
user = input("Enter any text: ")
print(user)