可变范围和python中的Try Catch

Question

import Image
import os
for dirname, dirs, files in os.walk("."):
    for filename in files:
        try:
            im = Image.open(os.path.join(dirname,filename))
        except IOError:
            print "error opening file :: "  + os.path.join(dirname,filename)
        print im.size

在这里,我试图打印目录(和子)中所有文件的大小.但我知道im在排队时超出范围im.size.但是如果不使用else或finally阻止我怎么办呢.

显示以下错误:

Traceback (most recent call last):
  File "batch.py", line 13, in <module>
    print im.size
NameError: name 'im' is not defined

Answer 1

"else"条款有什么问题？

for filename in files:
    try:
        im = Image.open(os.path.join(dirname,filename))
    except IOError, e:
        print "error opening file :: %s : %s" % (os.path.join(dirname,filename), e)
    else:
        print im.size

现在,既然你处于循环中,你也可以使用"继续"语句:

for filename in files:
    try:
        im = Image.open(os.path.join(dirname,filename))
    except IOError, e:
        print "error opening file :: %s : %s" % (os.path.join(dirname,filename), e)
        continue

    print im.size