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Asynchronous CSV reading/writing

Project description

aiocsv

Asynchronous CSV reading and writing.
AIOFile and Python's csv module combined.

Installation

pip3 install aiocsv

Usage

All objects in aiocsv pass keyword arguments to the underlying csv.reader/csv.writer/... instances.

import asyncio
import csv

from aiofile import AIOFile
from aiocsv import AsyncReader, AsyncDictReader, AsyncWriter, AsyncDictWriter

async def main():
    # simple reading
    async with AIOFile("some_file.csv", mode="r", encoding="utf-8-sig") as afp:
        async for row in AsyncReader(afp):
            print(row)  # row is a list

    # dict reading, tab-separated
    async with AIOFile("some_other_file.tsv", mode="r", encoding="utf-8-sig") as afp:
        async for row in AsyncDictReader(afp, delimiter="\t"):
            print(row)  # row is a dict

    # simple writing, "unix"-dialect
    async with AIOFile("new_file.csv", mode="r", encoding="utf-8-sig") as afp:
        writer = AsyncWriter(afp, dialect="unix")
        await writer.writerow(["name", "age"])
        await writer.writerows([
            ["John", 26], ["Sasha", 42], ["Hana", 37]
        ])

    # dict writing, all quoted, "NULL" for missing fields
    async with AIOFile("another_new_file.csv", mode="r", encoding="utf-8-sig") as afp:
        writer = AsyncDictWriter(afp, ["name", "age"], restval="NULL", quoting=csv.QUOTE_ALL)
        await writer.writeheader()
        await writer.writerow({"name": "John", "age": 26})
        await writer.writerows([
            {"name": "Sasha", "age": 42},
            {"name": "Hana"}
        ])

asyncio.run(main())

Reference

AsyncReader

class AsyncReader
 |  AsyncReader(aiofile: aiofile.aio.AIOFile, **csvreaderparams) -> None
 |  
 |  An object that iterates over lines in given aiofile.
 |  Additional keyword arguments are passed to the underlying csv.reader instance.
 |  
 |  Iterating over this object returns parsed rows (List[str]).
 |  
 |  ----------------------------------------------------------------------
 |  Methods defined here:
 |  
 |  __aiter__(self)
 |  
 |  async __anext__(self) -> List[str]
 |  
 |  __init__(self, aiofile: aiofile.aio.AIOFile, **csvreaderparams) -> None
 |      Initialize self.
 |  
 |  ----------------------------------------------------------------------
 |  Readonly properties defined here:
 |  
 |  dialect
 |  
 |  line_num
 |  
 |  ----------------------------------------------------------------------

AsyncDictReader

class AsyncDictReader(builtins.object)
 |  AsyncDictReader(aiofile: aiofile.aio.AIOFile, **csvdictreaderparams) -> None
 |  
 |  An object that iterates over lines in given aiofile.
 |  Additional keyword arguments are passed to the underlying csv.DictReader instance.
 |  
 |  If given csv file has no header, provide a 'fieldnames' keyword argument,
 |  like you would to csv.DictReader.
 |  
 |  Iterating over this object returns parsed rows (Dict[str, str]).
 |  
 |  ----------------------------------------------------------------------
 |  Methods defined here:
 |  
 |  __aiter__(self)
 |  
 |  async __anext__(self) -> Dict[str, str]
 |  
 |  __init__(self, aiofile: aiofile.aio.AIOFile, **csvdictreaderparams) -> None
 |      Initialize self.
 |  
 |  ----------------------------------------------------------------------
 |  Readonly properties defined here:
 |  
 |  dialect
 |  
 |  line_num
 |  
 |  ----------------------------------------------------------------------

AsyncWriter

class AsyncWriter(builtins.object)
 |  AsyncWriter(aiofile: aiofile.aio.AIOFile, **csvwriterparams) -> None
 |  
 |  An object that writes csv rows to the given aiofile.
 |  In this object "row" is a sequence of values.
 |  
 |  Additional keyword arguments are passed to the underlying csv.writer instance.
 |  
 |  ----------------------------------------------------------------------
 |  Methods defined here:
 |  
 |  __init__(self, aiofile: aiofile.aio.AIOFile, **csvwriterparams) -> None
 |      Initialize self.
 |  
 |  async writerow(self, row: Iterable[Any]) -> None
 |      Writes one row to the specified file.
 |  
 |  async writerows(self, rows: Iterable[Iterable[Any]]) -> None
 |      Writes multiple rows to the specified file.
 |      
 |      All rows are temporarly stored in RAM before actually being written to the file,
 |      so don't provide a generator of loads of rows.
 |  
 |  ----------------------------------------------------------------------
 |  Readonly properties defined here:
 |  
 |  dialect
 |  
 |  ----------------------------------------------------------------------

AsyncDictWriter

class AsyncDictWriter(builtins.object)
 |  AsyncDictWriter(aiofile: aiofile.aio.AIOFile, fieldnames: Sequence[str], **csvdictwriterparams) -> None
 |  
 |  An object that writes csv rows to the given aiofile.
 |  In this object "row" is a mapping from fieldnames to values.
 |  
 |  Additional keyword arguments are passed to the underlying csv.DictWriter instance.
 |  
 |  ----------------------------------------------------------------------
 |  Methods defined here:
 |  
 |  __init__(self, aiofile: aiofile.aio.AIOFile, fieldnames: Sequence[str], **csvdictwriterparams) -> None
 |      Initialize self.
 |  
 |  async writeheader(self) -> None
 |      Writes header row to the specified file.
 |  
 |  async writerow(self, row: Mapping[str, Any]) -> None
 |      Writes one row to the specified file.
 |  
 |  async writerows(self, rows: Iterable[Mapping[str, Any]]) -> None
 |      Writes multiple rows to the specified file.
 |      
 |      All rows are temporarly stored in RAM before actually being written to the file,
 |      so don't provide a generator of loads of rows.
 |  
 |  ----------------------------------------------------------------------
 |  Readonly properties defined here:
 |  
 |  dialect
 |  
 |  ----------------------------------------------------------------------

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