如果“<>条码>除外的代码运行,是因为提出了例外。 你掩盖了例外情况,使人难以知道什么是错的。

你的错误信息表明,你正在试图将档案中产生的错误固定下来。 但是,由于您的<代码>try的栏目围绕整个档案处理,处理过程中提出的例外情况,而不是公开的档案,将被误报为“不应公开档案”。 如果你真的必须处理这一例外情况,那么你就必须将<>条码>移至<>条码>之后。

Personally I d be inclined to simply ignore the exception and let the default handling of the exception halt execution:

with open( sample.txt , r ) as file:
    for line in file:
        (some action here)

如果你必须处理例外情形,那么就会发现你处理的特殊类别。 例如,仅处理<代码>IOError。 既然如此,如果出现故障,就会提出<条码>开放<>。

try:   
    with open( sample.txt , r ) as file:
        for line in file:
            (some action here)
except IOError:
    except IOError as (errno, strerror):
        print "I/O error({0}): {1}".format(errno, strerror)

然后,它没有在<代码>开放<>/代码>线上失效。 什么是例外?

try:
    file=open( sample.txt , r )
    for line in file:
          (some action here)
except:
    print "Exception:"
    import traceback; traceback.print_exc()

file.close()

That bare except catches all exceptions, including ones in the (some action here) part. Restructure that as:

try:
    inputfile = open( sample.txt ,  r )
except:
    print "Couldn t open file"
else:
    for line in inputfile: pass
    inputfile.close()

甚至更好:

with open( sample.txt ,  r ) as inputfile:
    for line in inputfile: pass

总的来说,在<条码>栏>内只列出最低限度的代码。 block,以便你不再偶然处理例外,否则你真的不愿意处理。

your code risks raising another assertion trying to close file if for some reason the open() call fails. This is because the file variable won t be set if open() raises an exception, and so your call further down will reference a variable that doesn t exist.

如有可能,利用声明:

with open( sample.txt ,  r ) as file:
    try:
        for line in file:
            (some action)
    except:
        print "Exception"
        import traceback; traceback.print_exc()

这将确保案卷随后结案,而不论在案卷中发生什么情况。

利用阅读线制作档案中所有内容的清单。 并且,你也无意在不至少印刷错误代码的情况下追捕一般错误。

try:
    file=open( sample.txt , r )
    for line in file.readlines():
          (some action here)
except Exception, e:
    print str(e)
file.close()

The actions I observe are that "sample.txt" is opened and the first line handled, the logic then falls through to the "except" clause.

是的,情况就是这样。 但只要档案存在,这只是。