同时写入多个文件

Question

我正在从事一个项目，涉及使用 Beaglebone 从多个传感器读取数据，然后将该数据传递到文本中 file.I我正在监测六种不同的肌肉，所以我有对应于每一种的文件。

现在，有 6 个传感器馈入 Beaglebone Black 的 ADC 引脚，我的代码指示 Beaglebone 为每个引脚创建 1 个单独的文件。每当我运行下面的代码时，我只得到一个文件（第一个函数运行s）。以前我没有包含 "while True:" 语句，这导致了 1-2 个读数和创建了六个文件。我添加了 "while True:" 以连续记录传感器的数据，因为我认为这就是我在每个文件中没有超过 2 个点的原因。

我的问题是：是否可以同时写入多个文件？我也可以将所有这些数据写入同一个文件，但我很想知道是什么导致此代码无法按预期运行（6 个文件。）

        #File save for left hamstring
def LeftHamAcquisition():
        HamLData = open('HamLeft' + '.txt', 'a+')
        file_name = os.path.join(/relevant file path/)
        while True:
                EMGhamL = ADC.read_raw('AIN1')
                HamLData.write(str(elapsed_milliseconds))
                HamLData.write('\t')
                HamLData.write(str(EMGhamL))
                HamLData.write('\n')

        #File save for right hams
def RighHamAcquisition():
        HamRData = open('HamRight' + '.txt', 'a+')
        file_name2 = os.path.join(/relevant file path/)
        while True:
                EMGhamR = ADC.read_raw('AIN2')
                HamRData.write(str(elapsed_milliseconds))
                HamRData.write('\t')
                HamRData.write(str(EMGhamR))
                HamRData.write('\n')


        #file save for left quad
def LeftQuadAcquisition():        
        QuadLData = open('QuadLeft' + '.txt', 'a+')
        file_name3 = os.path.join(/relevant file path/)
        while True:
                EMGquadL = ADC.read_raw('AIN3')
                QuadLData.write(str(elapsed_milliseconds))
                QuadLData.write('\t')
                QuadLData.write(str(EMGquadL))
                QuadLData.write('\n')

        #file save for right quad
def RightQuadAcquisition():
        QuadRData = open('QuadRight' + '.txt', 'a+')
        file_name4 = os.path.join(/relevant file path/)
        while True:
                EMGquadR = ADC.read_raw('AIN4')
                QuadRData.write(str(elapsed_milliseconds))
                QuadRData.write('\t')
                QuadRData.write(str(EMGquadR))
                QuadRData.write('\n')

        #file save for left vast
def LeftVastAcquisition():
        VastLData = open('VastLeft' + '.txt', 'a+')
        file_name5 = os.path.join(/relevant file path/)
        while True:
                EMGVastL = ADC.read_raw('AIN5')
                VastLData.write(str(elapsed_milliseconds))
                VastLData.write('\t')
                VastLData.write(str(EMGVastL))
                VastLData.write('\n')

        #file save for right vast
def RightVastAcquisition():
        VastRData = open('VastRight' + '.txt', 'a+')
        file_name6 = os.path.join(/relevant file path/)
        while True:
                EMGVastR = ADC.read_raw('AIN6')
                VastRData.write(str(elapsed_milliseconds))
                VastRData.write('\t')
                VastRData.write(str(EMGVastR))
                VastRData.write('\n')

#The Program
print "Press ctrl-C to end acquisition"

LeftHamAcquisition()
RighHamAcquisition()
LeftVastAcquisition()
RightVastAcquisition()
LeftQuadAcquisition()
RightQuadAcquisition()

try:
    pass
except KeyboardInterrupt:      
    raise data.close()

Answer 1

你的函数调用中有无限循环，所以它们永远不会 return。一个文件是由 LeftHamAcquisition 创建的，但由于它从未 return 编辑过，因此曾执行过 none 其他函数。您需要使用类似 multiprocessing module to get them to run in parallel. In particular, I would recommend multiprocessing pools and the apply_async 函数的东西：

import multiprocessing
import Queue
import time

# one global constant: the poison pill
# this could really be whatever you want - my string choice is arbitrary
STOP = "stop"

# change the signature of your function to accept a queue for the main 
# process to pass a poison pill
def LeftHamAcquisition(kill_queue):
    f_name = 'HamLeft.txt'

    # you aren't doing anything with "file_name" - should it be removed?
    # file_name = os.path.join(/relevant file path/)

    # use file context managers:
    with open(fname, 'a+') as HamLData:
        while True:

            # in the infinite loop, we add a check for the poison pill
            try:
                val = kill_queue.get(block=False)
                if val = STOP:
                    return # leave if the poison pill was sent
            except Queue.Empty:
                pass # ignore empty queue

            EMGhamL = ADC.read_raw('AIN1')
            HamLData.write(str(elapsed_milliseconds))
            HamLData.write('\t')
            HamLData.write(str(EMGhamL))
            HamLData.write('\n')

# ... the rest of your functions ...

#The Program
print "Press ctrl-C to end acquisition"

# a list of your functions
f_list = [
    LeftHamAcquisition,
    RighHamAcquisition,
    LeftVastAcquisition,
    RightVastAcquisition,
    LeftQuadAcquisition,
    RightQuadAcquisition,
]

pool = multiprocessing.Pool()    #c reate the worker pool
kill_queue = multiprocessing.Queue() # create the queue to pass poison pills

for f in f_list:
    # kick off the functions, passing them the poison pill queue
    pool.apply_async(f, args=(kill_queue))     
try:
    # put the main process to sleep while the workers do their thing
    while True:
        time.sleep(60)

except KeyboardInterrupt:      

    # close the workers nicely - put one poison pill on the queue for each
    for f in f_list:
        q.put(STOP)
    pool.close()
    pool.join()
    raise data.close()

而且，没有理由拥有这么多功能。它们都做同样的事情，只是使用不同的字符串和变量名。您应该将它们重构为一个可以将参数传递给的函数：

def acquisition(kill_queue, f_name, ain):

    with open(fname, 'a+') as f:
        while True:

            try:
                val = kill_queue.get(block=False)
                if val = STOP:
                    return
            except Queue.Empty:
                pass

            an_val = ADC.read_raw(ain)

            # where does "elapsed_milliseconds" come from? it's undefined
            # in your example code
            f.write("{}\t{}\n".format(elapsed_milliseconds, an_val))

使用这个函数，而不是在我的多处理示例中提供单个函数的列表，你可以重复使用这个函数，用不同的参数重复调用它（这是函数的全部要点）。

同时写入多个文件

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