在遞歸方法中保持計數？

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我正在使用Python。我正在努力保持遞歸方法。當我使用count+=1時出現錯誤。這是爲什麼？我在使用sum=sum+count時也出現錯誤。這是錯誤：在遞歸方法中保持計數？

local variable 'count' referenced before assignment

這裏是我的代碼：

def receiveOnePing(mySocket, ID, timeout, destAddr): 
    #receives ping 
    timeLeft = timeout 
    while 1: 
     startedSelect = time.time() 
     whatReady = select.select([mySocket], [], [], timeLeft) 
     howLongInSelect = (time.time() - startedSelect) 
     if whatReady[0] == []: # Timeout 
      return "Request timed out." 
     timeReceived = time.time() 
     recPacket, addr = mySocket.recvfrom(1024) 
     header = recPacket[20:28] 
     type, code, checksum, id, sequence= struct.unpack("bbHHh", header)  
     if id ==ID: 
      sizeofdouble = struct.calcsize("d")#returns size of structure 
      timeSent = struct.unpack("d", recPacket[28 : 28+sizeofdouble])[0] 
      print "Type:%d Code:%d Checksum:0x%08x Packet ID:%d Sequence:%d RTT:%d ms % (type, code, checksum, id, sequence, rtt) 
      count+=1 
     timeLeft = timeLeft - howLongInSelect 
     if timeLeft <= 0: 
      return "Request timed out." 
     else : 
      return "REPLY from %s " % destAddr

來源

2013-10-10 user2847851

格式代碼正確 –

你需要'計數= 0'顯然，如果你不先賦值count，那麼'count = count + 1'沒有任何意義。 – Shashank

相關http://stackoverflow.com/questions/19259837/i-cannot- print-the-final-value-of-variable/19259914＃19259914 –