Python生成器文件的产量

Question

I want to use a generator for my script but I get alwayse an exception:

Traceback (most recent call last):
  File "scan.py", line 56, in scan_m
    for line in ip_list:
  File "scan", line 46, in expand_ip_addr
    yield str(ip) + '\n'
UnboundLocalError: local variable 'ip' referenced before assignment

and here is my code, what should I change? I had never used a generator before.

def expand_ip_addr():
    with open('ip.txt', 'r') as file_in:
            #remove blank lines
        for line in file_in:

            if '/' in str(line):
                for ip in IPNetwork(str(line)):
                    yield str(ip
            else:
                line

def scan_m(ip_list):
    i = 1
    try:
        for line in ip_list:
            # do something with the line
            i = i + 1


def main():
    ip_list = expand_ip_addr()
    scan_m(ip_list)

if __name__ == "__main__":
    main()

---

update my mistake the else statement was wrong, sry

Answer 1

Change

for line in file_in.read().replace('\n\n', '\n'):

and

else:
    yield str(ip) + '\n'

to

for line in file_in:
    line = line.strip()
    if not line: continue

and

else:
    yield line + '\n'