July 2017
Intermediate to advanced
398 pages
11h 54m
Chinese
Content preview from Python数据处理
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78
｜
第
5
章
我们要用
pdfminer
将
PDF
转换成文本。首先安装这个库：
pip install pdfminer
安装好
pdfminer
，你就可以使用一个叫作
pdf2txt.py
的命令，将
PDF
文件转换成文本。
现在我们来试一下。运行下面的命令，将
PDF
转换成同一文件夹下的文本文件，这样所有
的数据都在同一文件夹下：
pdf2txt.py -o en-final-table9.txt EN-FINAL\ Table\ 9.pdf
第一个参数（
-o en-final-table9.txt
）是我们想要创建的文本文件。第二个参数（
EN-
FINAL\ TABLE\ 9.pdf
）是我们的
PDF
文件。确保大小写和文件名中的空格正确。空格前面
需要加一个反斜线（
\
）。这叫
转义
（
escaping
）。转义是告诉计算机，空格是输入内容的一
部分。
利用
Tab
自动补全
给你介绍一位终端里的新朋友：
Tab
键。对于上面命令的第二个参数，你可以先输入
EN
，然后按两下
Tab
键。如果只有一种备选的话，计算机会自动补全文件名。如果有
多种备选，计算机会发出警告音，并返回一系列备选。在输入又长又奇怪的文件夹或
文件名时，这种方法极为有用。
试试这个。切换到
home
目录（在基于
Unix
的系统是
cd ~/
，在
Windows
上是
cd %cd%
）。现在，假设你想进入
Documents
目录。试着输入
cd D
，然后按两下
Tab
键。发生了什么？
home
目录里还有哪些文件或文件夹以字母
D
开头？（可能是
Downloads
文件夹？）
现在试一下
cd ...
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.