python-random-access-file-reader | Low memory usage random access reader for csv | CSV Processing library

 by   jegesh Python Version: Current License: No License

kandi X-RAY | python-random-access-file-reader Summary

kandi X-RAY | python-random-access-file-reader Summary

python-random-access-file-reader is a Python library typically used in Utilities, CSV Processing applications. python-random-access-file-reader has no bugs, it has no vulnerabilities, it has build file available and it has low support. You can install using 'pip install python-random-access-file-reader' or download it from GitHub, PyPI.

Low memory usage random access reader for csv and general files
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              python-random-access-file-reader has a low active ecosystem.
              It has 7 star(s) with 4 fork(s). There are 1 watchers for this library.
              OutlinedDot
              It had no major release in the last 6 months.
              There are 3 open issues and 1 have been closed. On average issues are closed in 1 days. There are 1 open pull requests and 0 closed requests.
              It has a neutral sentiment in the developer community.
              The latest version of python-random-access-file-reader is current.

            kandi-Quality Quality

              python-random-access-file-reader has no bugs reported.

            kandi-Security Security

              python-random-access-file-reader has no vulnerabilities reported, and its dependent libraries have no vulnerabilities reported.

            kandi-License License

              python-random-access-file-reader does not have a standard license declared.
              Check the repository for any license declaration and review the terms closely.
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              Without a license, all rights are reserved, and you cannot use the library in your applications.

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              python-random-access-file-reader releases are not available. You will need to build from source code and install.
              Deployable package is available in PyPI.
              Build file is available. You can build the component from source.

            Top functions reviewed by kandi - BETA

            kandi has reviewed python-random-access-file-reader and discovered the below as its top functions. This is intended to give you an instant insight into python-random-access-file-reader implemented functionality, and help decide if they suit your requirements.
            • Returns a list of line data .
            • Get a list of line dictionaries .
            • Get the values from the given line .
            • Get a list of lines .
            • Initialize the parser .
            • Set the headers
            • Return the number of lines .
            • Return a list of line indexes .
            • Response headers .
            Get all kandi verified functions for this library.

            python-random-access-file-reader Key Features

            No Key Features are available at this moment for python-random-access-file-reader.

            python-random-access-file-reader Examples and Code Snippets

            No Code Snippets are available at this moment for python-random-access-file-reader.

            Community Discussions

            QUESTION

            Peformance issues reading CSV files in a Java (Spring Boot) application
            Asked 2022-Jan-29 at 12:37

            I am currently working on a spring based API which has to transform csv data and to expose them as json. it has to read big CSV files which will contain more than 500 columns and 2.5 millions lines each. I am not guaranteed to have the same header between files (each file can have a completly different header than another), so I have no way to create a dedicated class which would provide mapping with the CSV headers. Currently the api controller is calling a csv service which reads the CSV data using a BufferReader.

            The code works fine on my local machine but it is very slow : it takes about 20 seconds to process 450 columns and 40 000 lines. To improve speed processing, I tried to implement multithreading with Callable(s) but I am not familiar with that kind of concept, so the implementation might be wrong.

            Other than that the api is running out of heap memory when running on the server, I know that a solution would be to enhance the amount of available memory but I suspect that the replace() and split() operations on strings made in the Callable(s) are responsible for consuming a large amout of heap memory.

            So I actually have several questions :

            #1. How could I improve the speed of the CSV reading ?

            #2. Is the multithread implementation with Callable correct ?

            #3. How could I reduce the amount of heap memory used in the process ?

            #4. Do you know of a different approach to split at comas and replace the double quotes in each CSV line ? Would StringBuilder be of any healp here ? What about StringTokenizer ?

            Here below the CSV method

            ...

            ANSWER

            Answered 2022-Jan-29 at 02:56

            I don't think that splitting this work onto multiple threads is going to provide much improvement, and may in fact make the problem worse by consuming even more memory. The main problem is using too much heap memory, and the performance problem is likely to be due to excessive garbage collection when the remaining available heap is very small (but it's best to measure and profile to determine the exact cause of performance problems).

            The memory consumption would be less from the replace and split operations, and more from the fact that the entire contents of the file need to be read into memory in this approach. Each line may not consume much memory, but multiplied by millions of lines, it all adds up.

            If you have enough memory available on the machine to assign a heap size large enough to hold the entire contents, that will be the simplest solution, as it won't require changing the code.

            Otherwise, the best way to deal with large amounts of data in a bounded amount of memory is to use a streaming approach. This means that each line of the file is processed and then passed directly to the output, without collecting all of the lines in memory in between. This will require changing the method signature to use a return type other than List. Assuming you are using Java 8 or later, the Stream API can be very helpful. You could rewrite the method like this:

            Source https://stackoverflow.com/questions/70900587

            QUESTION

            Inserting json column in Bigquery
            Asked 2021-Jun-02 at 06:55

            I have a JSON that I want to insert into BQ. The column data type is STRING. Here is the sample JSON value.

            ...

            ANSWER

            Answered 2021-Jun-02 at 06:55

            I think there is an issue with how you escape the double quotes. I could reproduce the issue you describe, and fixed it by escaping the double quotes with " instead of a backslash \:

            Source https://stackoverflow.com/questions/67799161

            QUESTION

            Avoid repeated checks in loop
            Asked 2021-Apr-23 at 11:51

            I'm sorry if this has been asked before. It probably has, but I just have not been able to find it. On with the question:

            I often have loops which are initialized with certain conditions that affect or (de)activate certain behaviors inside them, but do not drastically change the general loop logic. These conditions do not change through the loop's operation, but have to be checked every iteration anyways. Is there a way to optimized said loop in a pythonic way to avoid doing the same check every single time? I understand this would be a compiler's job in any compiled language, but there ain't no compiler here.

            Now, for a specific example, imagine I have a function that parses a CSV file with a format somewhat like this, where you do not know in advance the columns that will be present on it:

            ...

            ANSWER

            Answered 2021-Apr-23 at 11:36

            Your code seems right to me, performance-wise.

            You are doing your checks at the beginning of the loop:

            Source https://stackoverflow.com/questions/67228959

            QUESTION

            golang syscall, locked to thread
            Asked 2021-Apr-21 at 15:29

            I am attempting to create an program to scrape xml files. I'm experimenting with go because of it's goroutines. I have several thousand files, so some type of multiprocessing is almost a necessity...

            I got a program to successfully run, and convert xml to csv(as a test, not quite the end result), on a test set of files, but when run with the full set of files, it gives this:

            ...

            ANSWER

            Answered 2021-Apr-21 at 15:25

            I apologize for not including the correct error. as the comments pointed out i was doing something dumb and creating a routine for every file. Thanks to JimB for correcting me, and torek for providing a solution and this link. https://gobyexample.com/worker-pools

            Source https://stackoverflow.com/questions/67182393

            QUESTION

            How to break up a string into a vector fast?
            Asked 2020-Jul-31 at 21:54

            I am processing CSV and using the following code to process a single line.

            play with code

            ...

            ANSWER

            Answered 2020-Jul-31 at 21:54

            The fastest way to do something is to not do it at all.

            If you can ensure that your source string s will outlive the use of the returned vector, you could replace your std::vector with std::vector which would point to the beginning of each substring. You then replace your identified delimiters with zeroes.

            [EDIT] I have not moved up to C++17, so no string_view for me :)

            NOTE: typical CSV is different from what you imply; it doesn't use escape for the comma, but surrounds entries with comma in it with double quotes. But I assume you know your data.

            Implementation:

            Source https://stackoverflow.com/questions/63197165

            QUESTION

            CSV Regex skipping first comma
            Asked 2020-May-11 at 22:02

            I am using regex for CSV processing where data can be in Quotes, or no quotes. But if there is just a comma at the starting column, it skips it.

            Here is the regex I am using: (?:,"|^")(""|[\w\W]*?)(?=",|"$)|(?:,(?!")|^(?!"))([^,]*?|)(?=$|,)

            Now the example data I am using is: ,"data",moredata,"Data" Which should have 4 matches ["","data","moredata","Data"], but it always skips the first comma. It is fine if there is quotes on the first column, or it is not blank, but if it is empty with no quotes, it ignores it.

            Here is a sample code I am using for testing purposes, it is written in Dart:

            ...

            ANSWER

            Answered 2020-May-11 at 22:02

            Investigating your expression

            Source https://stackoverflow.com/questions/61584722

            Community Discussions, Code Snippets contain sources that include Stack Exchange Network

            Vulnerabilities

            No vulnerabilities reported

            Install python-random-access-file-reader

            You can install using 'pip install python-random-access-file-reader' or download it from GitHub, PyPI.
            You can use python-random-access-file-reader like any standard Python library. You will need to make sure that you have a development environment consisting of a Python distribution including header files, a compiler, pip, and git installed. Make sure that your pip, setuptools, and wheel are up to date. When using pip it is generally recommended to install packages in a virtual environment to avoid changes to the system.

            Support

            For any new features, suggestions and bugs create an issue on GitHub. If you have any questions check and ask questions on community page Stack Overflow .
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