python with (as)语句实例详解

url = 'http://www.weather.com.cn/' + province + '/index.shtml'
with urlopen(url) as fp:
　　contents = fp.read().decode()

with open("aaa.txt","r") as f:
      line = f.readline()       # 调用文件的 readline()方法
      av=""
      while line:
        if len(line.strip())>0:
          if line.strip()[0].isdigit():
            a1=line
            bz=1
          if line.strip()[0].isalpha():
            a2=line
            bz=2
          if line.find(tmp_value)>-1:
            if bz==2:
              av=av+a1+a2
            if bz==1:
              line = f.readline()
              av=av+a1+line
          #print(line)
          line=f.readline()
          continue
if len(av)!=0:
  print(av)