文件修改

s = open('abc.txt','r')
u = s.read()
s.close()
p = ''
for i in u:
    if i == '世':
        i = '中'
        p = p + i
        continue
    if i == '界':
        i = '国'
        p = p + i
        continue
    p = p + i
print(p)
q = open('abc.txt','w')
q.write(p)
q.close()