bz2

Speed up reading in a compressed bz2 file ('rb' mode)

由 若如初见. 提交于 2021-02-11 14:21:37
问题 I have a BZ2 file of more than 10GB. I'd like to read it without decompressing it into a temporary file (it would be more than 50GB). With this method: import bz2, time t0 = time.time() time.sleep(0.001) # to avoid / by 0 with bz2.open("F:\test.bz2", 'rb') as f: for i, l in enumerate(f): if i % 100000 == 0: print('%i lines/sec' % (i/(time.time() - t0))) I can only read ~ 250k lines per second. On a similar file, first decompressed , I get ~ 3M lines per second, i.e. a x10 factor: with open("F

Using Javascript to make parallel server requests THREDDS OPeNDAP

由 流过昼夜 提交于 2019-12-12 03:15:15
问题 For the following THREDDS OPeNDAP server: http://data.nodc.noaa.gov/thredds/catalog/ghrsst/L2P/MODIS_T/JPL/2015/294/catalog.html I would like to note four Attributes of every file in there. The attributes are: northernmost lattitude; easternmost lattitude; westernmost lattitude; southernmost lattitude. These can be found under the Global attributes under: http://data.nodc.noaa.gov/thredds/dodsC/ghrsst/L2P/MODIS_T/JPL/2015/294/20151021-MODIS_T-JPL-L2P-T2015294235500.L2_LAC_GHRSST_N-v01.nc.bz2

Read simple/bz2-compressed-file(line by line) by detecting it is compressed or not (size of file is large)

由 巧了我就是萌 提交于 2019-12-11 02:59:12
问题 I wrote a code to read simple-text/bz2-compressed-file. I used magic-characters of bz2 file to detect the file is compressed or not NOTE "user may or may not provide file with proper extension" my code #include <iostream> #include <sstream> #include <vector> #include <boost/iostreams/filtering_stream.hpp> #include <boost/iostreams/copy.hpp> #include <boost/iostreams/filter/bzip2.hpp> // compile using // g++ -std=c++11 code.cpp -lboost_iostreams // run using // ./a.out < compressed_file // ./a

Spark: difference when read in .gz and .bz2

由 可紊 提交于 2019-12-09 00:39:25
问题 I normally read and write files in Spark using .gz, which the number of files should be the same as the number of RDD partitions. I.e. one giant .gz file will read in to a single partition. However, if I read in one single .bz2, would I still get one single giant partition? Or will Spark support automatic split one .bz2 to multiple partitions? Also, how do I know how many partitions it would be while Hadoop read in it from one bz2 file. Thanks! 回答1: However, if I read in one single .bz2,

Python: Convert Raw String to Bytes String without adding escape chraracters

由 坚强是说给别人听的谎言 提交于 2019-12-08 06:01:34
问题 I have a string: 'BZh91AY&SYA\xaf\x82\r\x00\x00\x01\x01\x80\x02\xc0\x02\x00 \x00!\x9ah3M\x07<]\xc9\x14\xe1BA\x06\xbe\x084' And I want: b'BZh91AY&SYA\xaf\x82\r\x00\x00\x01\x01\x80\x02\xc0\x02\x00 \x00!\x9ah3M\x07<]\xc9\x14\xe1BA\x06\xbe\x084' But I keep getting: b'BZh91AY&SYA\\xaf\\x82\\r\\x00\\x00\\x01\\x01\\x80\\x02\\xc0\\x02\\x00 \\x00!\\x9ah3M\\x07<]\\xc9\\x14\\xe1BA\\x06\\xbe\\x084' Context I scraped a string off of a webpage and stored it in the variable un . Now I want to decompress it

tarfile compressionerror bz2 module is not available

由 社会主义新天地 提交于 2019-12-08 04:26:00
问题 I'm trying to install twisted pip install https://pypi.python.org/packages/18/85/eb7af503356e933061bf1220033c3a85bad0dbc5035dfd9a97f1e900dfcb/Twisted-16.2.0.tar.bz2#md5=8b35a88d5f1a4bfd762a008968fddabf This is for a django-channels project and I'm having the following error problem Exception: Traceback (most recent call last): File "/home/petarp/.virtualenvs/ErasmusCloneFromGitHub/lib/python3.5/tarfile.py", line 1655, in bz2open import bz2 File "/usr/local/lib/python3.5/bz2.py", line 22, in

Python decompression relative performance?

由 我的未来我决定 提交于 2019-12-06 06:18:44
问题 TLDR; Of the various compression algorithms available in python gzip , bz2 , lzma , etc, which has the best decompression performance? Full discussion: Python 3 has various modules for compressing/decompressing data including gzip , bz2 and lzma . gzip and bz2 additionally have different compression levels you can set. If my goal is to balance file size (/compression ratio) and decompression speed (compression speed is not a concern), which is going to be the best choice? Decompression speed

Python decompression relative performance?

由 和自甴很熟 提交于 2019-12-04 09:24:31
TLDR; Of the various compression algorithms available in python gzip , bz2 , lzma , etc, which has the best decompression performance? Full discussion: Python 3 has various modules for compressing/decompressing data including gzip , bz2 and lzma . gzip and bz2 additionally have different compression levels you can set. If my goal is to balance file size (/compression ratio) and decompression speed (compression speed is not a concern), which is going to be the best choice? Decompression speed is more important than file size, but as the uncompressed files in question would be around 600-800MB

Spark: difference when read in .gz and .bz2

由 坚强是说给别人听的谎言 提交于 2019-12-01 07:35:27
I normally read and write files in Spark using .gz, which the number of files should be the same as the number of RDD partitions. I.e. one giant .gz file will read in to a single partition. However, if I read in one single .bz2, would I still get one single giant partition? Or will Spark support automatic split one .bz2 to multiple partitions? Also, how do I know how many partitions it would be while Hadoop read in it from one bz2 file. Thanks! However, if I read in one single .bz2, would I still get one single giant partition? Or will Spark support automatic split one .bz2 to multiple
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