python字符串条带不适用于尾随双引号

Question

我试图使用python脚本自动完成一个任务，但遇到了这种奇怪的现象。我在“所以”中查找了相同的内容，但这略有不同，所以我在这里使用简化的示例。

下面有一个名为test1.txt的文件。

"https://papers.nips.cc/paper/7286-efficient-algorithms-for-non-convex-isotonic-regression-through-submodular-optimization" ## Efficient Algorithms for Non-convex Isotonic Regression through Submodular Optimization
"https://papers.nips.cc/paper/7287-structure-aware-convolutional-neural-networks" ## Structure-Aware Convolutional Neural Networks
"https://papers.nips.cc/paper/7288-kalman-normalization-normalizing-internal-representations-across-network-layers" ## Kalman Normalization: Normalizing Internal Representations Across Network Layers
"https://papers.nips.cc/paper/7289-hogwild-gibbs-can-be-panaccurate" ## HOGWILD!-Gibbs can be PanAccurate

和python脚本quest.py

import re

with open('test1.txt') as f:
    for line in f:
        #print line
        link = re.sub(" ##.*","",line)
        print link
        link1 = link.strip('\"')
        print link1

当我用python quest.py执行它时，我得到

"https://papers.nips.cc/paper/7286-efficient-algorithms-for-non-convex-isotonic-regression-through-submodular-optimization"

https://papers.nips.cc/paper/7286-efficient-algorithms-for-non-convex-isotonic-regression-through-submodular-optimization"

"https://papers.nips.cc/paper/7287-structure-aware-convolutional-neural-networks"

https://papers.nips.cc/paper/7287-structure-aware-convolutional-neural-networks"

"https://papers.nips.cc/paper/7288-kalman-normalization-normalizing-internal-representations-across-network-layers"

https://papers.nips.cc/paper/7288-kalman-normalization-normalizing-internal-representations-across-network-layers"

"https://papers.nips.cc/paper/7289-hogwild-gibbs-can-be-panaccurate"

https://papers.nips.cc/paper/7289-hogwild-gibbs-can-be-panaccurate"

我希望第一次打印链接与周围双引号(=链接)，然后没有双引号(=链接1)。但是为什么我会看到link1的双引号呢？

Answer 1

Python的str.strip([chars])将移除前导和尾随的chars，但一旦到达不在chars中的字符，就会停止。

看起来您的link以换行符结束，甚至在到达双引号之前就停止了剥离。(提示：print只添加一个换行符，在输出中有两个换行符。)

去掉双引号和换行符：

link1 = link.strip('"\n')

此外，值得一提的是(如@glibdud注释中的注释)，链接之所以以换行符结尾，是因为文件迭代器没有删除换行符，sub表达式也没有(因为.不包括换行符；要包含它，需要添加re.DOTALL regex标志)。

Answer 2

当您想要打印没有引号时，只需去掉双引号和换行符，当要用双引号打印时，只需去掉新行即可。

import re

with open('file.txt') as f:
    for line in f:
        if line.strip():
            #print line
            link = re.sub(" ##.*", "", line)
            #Print with double quotes
            print link.strip('\n')
            #Print without double quotes by replacing double quotes with empty char
            print link.strip('"\n')

            #Print without double quotes by removing double quotes entirely
            #print link.strip("\"")

然后输出将是

"https://papers.nips.cc/paper/7286-efficient-algorithms-for-non-convex-isotonic-regression-through-submodular-optimization"
https://papers.nips.cc/paper/7286-efficient-algorithms-for-non-convex-isotonic-regression-through-submodular-optimization
"https://papers.nips.cc/paper/7287-structure-aware-convolutional-neural-networks"
https://papers.nips.cc/paper/7287-structure-aware-convolutional-neural-networks
"https://papers.nips.cc/paper/7288-kalman-normalization-normalizing-internal-representations-across-network-layers"
https://papers.nips.cc/paper/7288-kalman-normalization-normalizing-internal-representations-across-network-layers
"https://papers.nips.cc/paper/7289-hogwild-gibbs-can-be-panaccurate"
https://papers.nips.cc/paper/7289-hogwild-gibbs-can-be-panaccurate