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Question

進出口新Python和編程，但不能Python的全局變量似乎明白了爲什麼這個功能不會更新全局變量

global weight 
weight = 'value' 
def GetLiveWeight(): 
    SetPort() 
    while interupt == False: 
     port.write(requestChar2) 
     liveRaw = port.read(9) 
     liveRaw += port.read(port.inWaiting()) 
     time.sleep(0.2) 
     weight = liveRaw.translate(None, string.letters) 
    return weight 

我也試過這種

weight = 'value' 
def GetLiveWeight(): 
    global weight 
    SetPort() 
    while interupt == False: 
     port.write(requestChar2) 
     liveRaw = port.read(9) 
     liveRaw += port.read(port.inWaiting()) 
     time.sleep(0.2) 
     weight = liveRaw.translate(None, string.letters) 
    return weight 

try: 
    threading.Thread(target = GetLiveWeight).start() 
    print liveWeight 
except: 
    print "Error: unable to start thread" 

Answer 1

您需要聲明那weight是全球裏面GetLiveWeight，不在它之外。

weight = 'value' 
def GetLiveWeight(): 
    global weight 

的global statement告訴Python的GetLiveWeight功能的範圍內，weight指的是全局變量weight，而不是一些新的局部變量weight。