可变范围并尝试在python中捕获 [英] Variable scope and Try Catch in python

问题描述

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，我尝试打印目录(和子目录)中所有文件的大小.但是我知道im在行im.size中时不在范围内.但是，如果不使用else或finally块，该怎么办呢?

Here I'm trying to print the size of all the files in a directory (and sub). But I know im is outside the scope when in the line im.size. But how else do I do it without using else or finally blocks.

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

推荐答案

"else"子句有什么问题?

What's wrong with the "else" clause ?

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，由于您处于循环状态，因此还可以使用"continue"语句:

Now since you're in a loop, you can also use a "continue" statement:

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

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