Python write to a gzip file

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Table of Contents Previous: bz2 — bzip2 compression Next: tarfile — Tar archive access. Some of the features described here may not be available in earlier versions of Python. Now available for Python 3! Buy the book! The gzip module provides a file-like interface to GNU zip files, using zlib to compress and uncompress the data. The module-level function open creates an instance of the file-like class GzipFile. The usual methods for writing and reading data are provided. To write data into a compressed file, open the file with mode 'w'. Different amounts of compression can be used by passing a compresslevel argument. Valid values range from 1 to 9, inclusive. Lower values are faster and result in less compression. Higher values are slower and compress more, up to a point. The center column of numbers in the output of the script is the size in bytes of the files produced. As you see, for this input data, the higher compression values do not necessarily pay off in decreased storage space. Results will vary, depending on the input data. A GzipFile instance also includes a writelines method that can be used to write a sequence of strings. To read data back from previously compressed files, simply open the file with mode 'r'. The seek position is relative to the uncompressed data, so the caller does not even need to know that the data file is compressed. When working with a data stream instead of a file, use the GzipFile class directly to compress or uncompress it. This is useful when the data is being transmitted over a socket or from read an existing already open file handle. A StringIO buffer can also be used. When re-reading the previously compressed data, I pass an explicit length to read. If you are working with streams of compressed data, you may want to prefix the data with an integer representing the actual amount of data to be read. Last updated on Mar 16, Created using Sphinx. Design based on "Leaves" by SmallPark. Available In: 1. The same line, over and over. Starting at position 5 for 10 bytes: nts of the True. Note When re-reading the previously compressed data, I pass an explicit length to read.

Reading and Writing Files in Python


By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. Following tutorials and examples found in blogs and in other threads here, it appears that the way to write to a. When writing to a file opened in binary mode, you must write bytes, not string. Encode your string using str. The documentation has a couple of handy examples on usage. How are we doing? Please help us improve Stack Overflow. Take our short survey. Learn more. Writing text to gzip file Ask Question. Asked 2 years ago. Active 1 year, 2 months ago. Viewed 7k times. AgvaniaRekuva AgvaniaRekuva 2 2 silver badges 10 10 bronze badges. Active Oldest Votes. Instead of 'Hello world! Sven the example is to demonstrate how you would write strings via a variable -- you'd have to call string. I assumed it would be easier to explain like this. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown. The Overflow Blog. Q2 Community Roadmap. The Unfriendly Robot: Automatically flagging unwelcoming comments. Featured on Meta. Community and Moderator guidelines for escalating issues via new response…. Feedback on Q2 Community Roadmap. Triage needs to be fixed urgently, and users need to be notified upon…. Technical site integration observational experiment live on Stack Overflow. Dark Mode Beta - help us root out low-contrast and un-converted bits. Related Hot Network Questions. Question feed. Stack Overflow works best with JavaScript enabled.

Python gzip – compress decompress


This module provides a simple interface to compress and decompress files just like the GNU programs gzip and gunzip would. The data compression is provided by the zlib module. The gzip module provides the GzipFile class, as well as the opencompress and decompress convenience functions. The GzipFile class reads and writes gzip -format files, automatically compressing or decompressing the data so that it looks like an ordinary file object. Note that additional file formats which can be decompressed by the gzip and gunzip programs, such as those produced by compress and packare not supported by this module. Open a gzip-compressed file in binary or text mode, returning a file object. The filename argument can be an actual filename a str or bytes objector an existing file object to read from or write to. The mode argument can be any of 'r''rb''a''ab''w''wb''x' or 'xb' for binary mode, or 'rt''at''wt'or 'xt' for text mode. The default is 'rb'. The compresslevel argument is an integer from 0 to 9, as for the GzipFile constructor. For binary mode, this function is equivalent to the GzipFile constructor: GzipFile filename, mode, compresslevel. In this case, the encodingerrors and newline arguments must not be provided. For text mode, a GzipFile object is created, and wrapped in an io. TextIOWrapper instance with the specified encoding, error handling behavior, and line ending s. Changed in version 3. Constructor for the GzipFile class, which simulates most of the methods of a file objectwith the exception of the truncate method. At least one of fileobj and filename must be given a non-trivial value. The new class instance is based on fileobjwhich can be a regular file, an io. BytesIO object, or any other object which simulates a file. It defaults to Nonein which case filename is opened to provide a file object. When fileobj is not Nonethe filename argument is only used to be included in the gzip file header, which may include the original filename of the uncompressed file. It defaults to the filename of fileobjif discernible; otherwise, it defaults to the empty string, and in this case the original filename is not included in the header. The mode argument can be any of 'r''rb''a''ab''w''wb''x'or 'xb'depending on whether the file will be read or written. The default is the mode of fileobj if discernible; otherwise, the default is 'rb'. Note that the file is always opened in binary mode. To open a compressed file in text mode, use open or wrap your GzipFile with an io. The compresslevel argument is an integer from 0 to 9 controlling the level of compression; 1 is fastest and produces the least compression, and 9 is slowest and produces the most compression. The default is 9. The mtime argument is an optional numeric timestamp to be written to the stream when compressing. All gzip compressed streams are required to contain a timestamp. If omitted or Nonethe current time is used. This module ignores the timestamp when decompressing; however, some programs, such as gunzipmake use of it. The format of the timestamp is the same as that of the return value of time. This also allows you to pass an io. BytesIO object opened for writing as fileobjand retrieve the resulting memory buffer using the io. GzipFile supports the io.

Python Support for gzip files (gzip)


This module provides a simple interface to compress and decompress files just like the GNU programs gzip and gunzip would. The data compression is provided by the zlib module. The gzip module provides the GzipFile class, as well as the opencompress and decompress convenience functions. The GzipFile class reads and writes gzip -format files, automatically compressing or decompressing the data so that it looks like an ordinary file object. Note that additional file formats which can be decompressed by the gzip and gunzip programs, such as those produced by compress and packare not supported by this module. Open a gzip-compressed file in binary or text mode, returning a file object. The filename argument can be an actual filename a str or bytes objector an existing file object to read from or write to. The mode argument can be any of 'r''rb''a''ab''w''wb''x' or 'xb' for binary mode, or 'rt''at''wt'or 'xt' for text mode. The default is 'rb'. The compresslevel argument is an integer from 0 to 9, as for the GzipFile constructor. For binary mode, this function is equivalent to the GzipFile constructor: GzipFile filename, mode, compresslevel. In this case, the encodingerrors and newline arguments must not be provided. For text mode, a GzipFile object is created, and wrapped in an io. TextIOWrapper instance with the specified encoding, error handling behavior, and line ending s. Changed in version 3. An exception raised for invalid gzip files. It inherits OSError. EOFError and zlib. Constructor for the GzipFile class, which simulates most of the methods of a file objectwith the exception of the truncate method. At least one of fileobj and filename must be given a non-trivial value. The new class instance is based on fileobjwhich can be a regular file, an io. BytesIO object, or any other object which simulates a file. It defaults to Nonein which case filename is opened to provide a file object. When fileobj is not Nonethe filename argument is only used to be included in the gzip file header, which may include the original filename of the uncompressed file. It defaults to the filename of fileobjif discernible; otherwise, it defaults to the empty string, and in this case the original filename is not included in the header. The mode argument can be any of 'r''rb''a''ab''w''wb''x'or 'xb'depending on whether the file will be read or written. The default is the mode of fileobj if discernible; otherwise, the default is 'rb'. Note that the file is always opened in binary mode. To open a compressed file in text mode, use open or wrap your GzipFile with an io. The compresslevel argument is an integer from 0 to 9 controlling the level of compression; 1 is fastest and produces the least compression, and 9 is slowest and produces the most compression. The default is 9. The mtime argument is an optional numeric timestamp to be written to the last modification time field in the stream when compressing. It should only be provided in compression mode.

Example Uses of the Linux gzip Command

By default when you compress a file or folder using the gzip command it will have the same file name as it did before but with the extension. The simplest way to compress a single file using gzip is to run the following command:. Some files compress better than others. Other file types such as JPEG images and MP3 audio files do not compress at all well and the file may actually increase in size after running the gzip command against it. JPEG images and MP3 audio files are already compressed and therefore the gzip command simply adds to it rather than compressing it. Sometimes a file cannot be compressed. To force the gzip command to do its stuff simply run the following command:. By default when you compress a file using the gzip command you end up with a new file with the extension. To compress the file and keep the original file must specify the -k flag:. I you run the following command you would end up with a file called mydocument. The whole point of compressing files is about saving disk space or to reduce the size of a file prior to sending it over a network. The gzip command provides the kind of statistics you require when checking for compression performance. This process doesn't create one file called foldername. Instead, it traverses the directory structure and compresses each file in that folder structure. To compress the folder structure as one file you are better off creating a tar file and then gzipping the tar file. You can compress a file in different ways. For example, you can go for a smaller compression which will work faster or you can go for maximum compression which has the tradeoff of taking longer to run. The gzip command should not be used when working with standard zip files. You can use the zip command and unzip command for handling those files. Linux Switching from Windows. Tweet Share Email. The gzip command is a common way of compressing files within Linux. To compress a file called mydocument. The gzip command only attempts to compress regular files and folders. Use the following command to decompress a gzip archive:. To decompress the mydocument. To get the list of statistics run the following command:. The information returned by the above command is as follows:.

Python Tutorial: Zip Files - Creating and Extracting Zip Archives



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