Question

我是python的新手。我正面临着“wget”以及“urllib.urlretrieve（str（myurl），tail）”的问题

当我运行脚本时，它正在下载文件，但文件名以“？”结尾

我的完整代码：

import os
import wget
import urllib
import subprocess
with open('/var/log/na/na.access.log') as infile, open('/tmp/reddy_log.txt', 'w') as outfile:
    results = set()
    for line in infile:
        if ' 200 ' in line:
            tokens = line.split()
            results.add(tokens[6]) # 7th token
    for result in sorted(results):
        print >>outfile, result
with open ('/tmp/reddy_log.txt') as infile:
     results = set()
     for line in infile:
     head, tail = os.path.split(line)
                print tail
                myurl = "http://data.xyz.com" + str(line)
                print myurl
                wget.download(str(myurl))
                #  urllib.urlretrieve(str(myurl),tail)

输出：

# python last.py
0011400026_recap.xml

http://data.na.com/feeds/mobile/android/v2.0/video/games/high/0011400026_recap.xml

latest_1.xml

http://data.na.com/feeds/mobile/iphone/article/league/news/latest_1.xml

currenttime.js

列出文件：

# ls
0011400026_recap.xml?                   currenttime.js?  latest_1.xml?      today.xml?

Answer 1

您所经历的行为的可能解释是您这样做不清理您的输入line

with open ('/tmp/reddy_log.txt') as infile:
     ...
     for line in infile:
         ...
         myurl = "http://data.xyz.com" + str(line)
         wget.download(str(myurl))

迭代文件对象时，（for line in infile:）字符串你得到的是换行符（'\n'） - 如果你没有在使用line之前删除换行符，哦，换行符仍然存在于您使用line ...

所产生的内容中

作为这个概念的一个例子，请看一下成绩单我做过的测试

08:28 $ cat > a_file
a
b
c
08:29 $ cat > test.py
data = open('a_file')
for line in data:
    new_file = open(line, 'w')
    new_file.close() 
08:31 $ ls
a_file  test.py
08:31 $ python test.py
08:31 $ ls
a?  a_file  b?  c?  test.py
08:31 $ ls -b
a\n  a_file  b\n  c\n  test.py
08:31 $

如您所见，我从文件中读取行并使用创建一些文件 line作为文件名，猜猜ls列出的文件名是什么最后有一个? - 但我们可以做得更好，正如它在中所解释的那样精细的ls

手册页

  -b, --escape
         print C-style escapes for nongraphic characters

并且，正如您在ls -b的输出中看到的那样，文件名不是以问号结束（它只是默认使用的占位符通过ls程序，但由换行符终止。

虽然我喜欢它，但我不得不说你应该避免使用临时文件，用于存储计算的中间结果。

Python的一个很好的功能是存在生成器表达式，如果您愿意，可以按如下方式编写代码

import wget

# you matched on a '200' on the whole line, I assume that what
# you really want is to match a specific column, the 'error_column'
# that I symbolically load from an external resource
from my_constants import error_column, payload_column

# here it is a sequence of generator expressions, each one relying
# on the previous one

# 1. the lines in the file, stripped from the white space
#    on the right (the newline is considered white space)
#    === not strictly necessary, just convenient because
#    === below we want to test for non-empty lines
lines = (line.rstrip() for line in open('whatever.csv'))

# 2. the lines are converted to a list of 'tokens' 
all_tokens = (line.split() for line in lines if line)

# 3. for each 'tokens' in the 'all_tokens' generator expression, we
#    check for the code '200' and possibly generate a new target
targets = (tokens[payload_column] for tokens in all_tokens if tokens[error_column]=='200')

# eventually, use the 'targets' generator to proceed with the downloads
for target in targets: wget.download(target)

不要被评论的数量所迷惑，我的代码没有评论

import wget
from my_constants import error_column

lines = (line.rstrip() for line in open('whatever.csv'))
all_tokens = (line.split() for line in lines if line)
targets = (tokens[payload_column] for tokens in all_tokens if tokens[error_column]=='200')

for target in targets: wget.download(target)

在python中面对“wget”的问题

1 个答案: