使用 python 将 CSV 转换为 AVRO

Question

我有以下 csv ：

field1;field2;field3;field4;field5;field6;field7;field8;field9;field10;field11;field12;
eu;4523;35353;01/09/1999; 741 ; 386 ; 412 ; 86 ; 1.624 ; 1.038 ; 469 ; 117 ;

我想将其转换为 avro。我创建了以下 avro 架构：

{"namespace": "forecast.avro",
 "type": "record",
 "name": "forecast",
 "fields": [
     {"name": "field1", "type": "string"},
     {"name": "field2", "type": "string"},
     {"name": "field3", "type": "string"},
     {"name": "field4", "type": "string"},
     {"name": "field5", "type": "string"},
     {"name": "field6", "type": "string"},
     {"name": "field7", "type": "string"},
     {"name": "field8", "type": "string"},
     {"name": "field9", "type": "string"},
     {"name": "field10", "type": "string"},
     {"name": "field11", "type": "string"},
     {"name": "field12", "type": "null"}
 ]
}

我的代码是下一个：

import avro.schema
from avro.datafile import DataFileReader, DataFileWriter
from avro.io import DatumReader, DatumWriter
import csv
from collections import namedtuple


FORECAST = "forecast.csv"
fields = ("field1", "field2", "field3", "field4", "field5", "field6", "field7", "field8", "field9", "field10", "field11", "field12")
forecastRecord = namedtuple('forecastRecord', fields)

def read_forecast_data(path):
    with open(path, 'rU') as data:
        data.readline()
        reader = csv.reader(data, delimiter = ";")
        for row in map(forecastRecord._make, reader):
            print(row)
            yield row

if __name__=="__main__":
    for row in read_forecast_data(FORECAST):
        print (row)
        break

def parse_schema(path="forecast.avsc"):
    with open(path, 'r') as data:
        return avro.schema.parse(data.read())
def serialize_records(records, outpath="forecast.avro"):
    schema = parse_schema()
    with open(outpath, 'w') as out:
        writer = DataFileWriter(out, DatumWriter(), schema)
        for record in records:
            record = dict((f, getattr(record, f)) for f in record._fields)
            writer.append(record)
if __name__ == "__main__":
    serialize_records(read_forecast_data(FORECAST))

当我运行代码时，我收到错误消息，即数据不是当前模式的示例。我一次又一次地检查了我的模式以发现任何不一致之处，但直到现在我还没有找到任何不一致之处。有人可以帮助我吗？

Answer 1

当我按编写的方式运行您的代码时，我收到错误消息TypeError: Expected 12 arguments, got 13，for row in map(forecastRecord._make, reader):因为您的 CSV 以 a 结尾;，因此有 13 个字段。

一旦我删除了那些尾随;s，我就可以运行该示例并获得有关架构不匹配的相同错误。原因是field12在您的架构中被定义为一种类型，null但在数据中它是一种string类型（具有值"117"）。

如果您将 avsc 文件更改为，{"name": "field12", "type": "string"}则它可以工作。