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241 lines
3.4 KiB
Markdown
241 lines
3.4 KiB
Markdown
# gzip, zipfile, tarfile 模块：处理压缩文件
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In [1]:
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```py
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import os, shutil, glob
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import zlib, gzip, bz2, zipfile, tarfile
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```
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gzip
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## zilb 模块
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`zlib` 提供了对字符串进行压缩和解压缩的功能：
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In [2]:
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```py
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orginal = "this is a test string"
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compressed = zlib.compress(orginal)
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print compressed
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print zlib.decompress(compressed)
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```
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```py
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x<EFBFBD>+<EFBFBD><EFBFBD>,V<EFBFBD>D<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>⒢̼tS<EFBFBD><EFBFBD><EFBFBD>
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this is a test string
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```
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同时提供了两种校验和的计算方法：
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In [3]:
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```py
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print zlib.adler32(orginal) & 0xffffffff
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```
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```py
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1407780813
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```
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In [4]:
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```py
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print zlib.crc32(orginal) & 0xffffffff
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```
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```py
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4236695221
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```
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## gzip 模块
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`gzip` 模块可以产生 `.gz` 格式的文件，其压缩方式由 `zlib` 模块提供。
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我们可以通过 `gzip.open` 方法来读写 `.gz` 格式的文件：
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In [5]:
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```py
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content = "Lots of content here"
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with gzip.open('file.txt.gz', 'wb') as f:
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f.write(content)
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```
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读：
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In [6]:
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```py
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with gzip.open('file.txt.gz', 'rb') as f:
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file_content = f.read()
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print file_content
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```
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```py
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Lots of content here
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```
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将压缩文件内容解压出来：
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In [7]:
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```py
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with gzip.open('file.txt.gz', 'rb') as f_in, open('file.txt', 'wb') as f_out:
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shutil.copyfileobj(f_in, f_out)
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```
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此时，目录下应有 `file.txt` 文件，内容为：
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In [8]:
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```py
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with open("file.txt") as f:
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print f.read()
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```
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```py
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Lots of content here
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```
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In [9]:
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```py
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os.remove("file.txt.gz")
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```
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### bz2 模块
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`bz2` 模块提供了另一种压缩文件的方法：
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In [10]:
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```py
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orginal = "this is a test string"
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compressed = bz2.compress(orginal)
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print compressed
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print bz2.decompress(compressed)
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```
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```py
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BZh91AY&SY*<EFBFBD><EFBFBD>v <EFBFBD><EFBFBD>@"<EFBFBD><EFBFBD> 10"zi<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>FLT`<EFBFBD>軒)„<EFBFBD>P<EFBFBD>˰
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this is a test string
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```
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## zipfile 模块
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产生一些 `file.txt` 的复制：
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In [11]:
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```py
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for i in range(10):
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shutil.copy("file.txt", "file.txt." + str(i))
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```
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将这些复制全部压缩到一个 `.zip` 文件中：
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In [12]:
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```py
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f = zipfile.ZipFile('files.zip','w')
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for name in glob.glob("*.txt.[0-9]"):
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f.write(name)
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os.remove(name)
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f.close()
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```
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解压这个 `.zip` 文件，用 `namelist` 方法查看压缩文件中的子文件名：
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In [13]:
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```py
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f = zipfile.ZipFile('files.zip','r')
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print f.namelist()
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```
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```py
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['file.txt.9', 'file.txt.6', 'file.txt.2', 'file.txt.1', 'file.txt.5', 'file.txt.4', 'file.txt.3', 'file.txt.7', 'file.txt.8', 'file.txt.0']
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```
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使用 `f.read(name)` 方法来读取 `name` 文件中的内容：
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In [14]:
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```py
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for name in f.namelist():
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print name, "content:", f.read(name)
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f.close()
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```
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```py
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file.txt.9 content: Lots of content here
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file.txt.6 content: Lots of content here
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file.txt.2 content: Lots of content here
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file.txt.1 content: Lots of content here
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file.txt.5 content: Lots of content here
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file.txt.4 content: Lots of content here
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file.txt.3 content: Lots of content here
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file.txt.7 content: Lots of content here
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file.txt.8 content: Lots of content here
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file.txt.0 content: Lots of content here
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```
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可以用 `extract(name)` 或者 `extractall()` 解压单个或者全部文件。
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## tarfile 模块
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支持 `.tar` 格式文件的读写：
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例如可以这样将 `file.txt` 写入：
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In [15]:
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```py
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f = tarfile.open("file.txt.tar", "w")
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f.add("file.txt")
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f.close()
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```
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清理生成的文件：
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In [16]:
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```py
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os.remove("file.txt")
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os.remove("file.txt.tar")
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os.remove("files.zip")
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``` |