列表项到整数的转换触发python3中的语法错误

Question

import re
import socket
import sys

def Check(ip,port):    
    try:
        s = socket.socket()
        s.settimeout(0.3)
        s.connect((ip,port))
        return s.recv(512)
    except:
        pass    

def Scan():
    start = sys.argv[1]
    end = sys.argv[2]    
    endip = end.partition('.')
    currentip = start.split('.')
    while not (currentip == endip):
        targetip = currentip[0]+"."+currentip[1]+"."+currentip[2]+"."+currentip[3]
        print("Checking: "+targetip+"\n")
        result = Check(targetip,21)
        if result:
            if re.search("FTP",result.decode('utf-8')):
                retard = open('ftps.txt','a')
                retard.write(targetip+"\n")
                retard.close()
        if (int(currentip[3]) < 255) and (int(currentip[0]) != int(endip[0])) and (int(currentip[1]) != int(endip[1])) and (int(currentip[2]) != int(endip[2])) and (int(currentip[3]) != int(endip[3])+1):
            int(currentip[3]) += 1
        elif (int(currentip[3]) == 255) and (int(currentip[0]) != int(endip[0])) and (int(currentip[1]) != int(endip[1])) and (int(currentip[2]) != int(endip[2])) and (int(currentip[3]) != int(endip[3])+1):
            if (int(currentip[2]) < 255):
                int(currentip[2]) += 1
                int(currentip[3]) = 0
            elif (int(currentip[2]) == 255):
                if (int(currentip[1]) < 255):
                    int(currentip[1]) += 1
                    int(currentip[2]) = 0
                    int(currentip[3]) = 0
                elif (int(currentip[0]) < int(endip[0])) and (int(currentip[0]) != 255) and (int(currentip[1]) == 255):
                    int(currentip[0]) += 1
                    int(currentip[1]) = 0
                    int(currentip[2]) = 0
                    int(currentip[3]) = 0
Scan()

int(currentip[0]) += 1会导致错误，而转换其他与转换方式完全相同的项则不会触发任何错误

  File "ftpscan.py", line 46
    int(currentip[0]) += 1
    ^
SyntaxError: cannot assign to function call

Answer 1

基本上，i += 1与i = i + 1相同

就你而言 int(currentip[0]) += 1，与int(currentip[0]) = int(currentip[0]) + 1相同

因此，从技术上讲，您不能分配给函数调用。 相反，这应该是可行的

currentip[0] = int(currentip[0]) + 1