Yelp 数据集：Json 到 csv 转换器 (python 3)

Question

所以，我正在尝试使用 Yelp 数据集。我正在使用 python 3！我找到了将 json 文件转换为 csv 的代码，我在 Windows 上打开 cmd 并输入： C:\Users\AppData\Local\Programs\Python\Python36-32>python.exe json_to_csv_converter.py review.json

该命令不再给我错误，但它实际上没有转换（没有 csv 文件作为输出）。

你能帮我理解为什么它不起作用吗？

converter.py里面的代码是：

import argparse
import collections
import csv
import json


def read_and_write_file(json_file_path, csv_file_path, column_names):
    with open(csv_file_path, 'w+') as fout:
        csv_file = csv.writer(fout)
    csv_file.writerow(list(column_names))
    with open(json_file_path, encoding="utf8") as fin:

        for line in fin:
            line_contents = json.loads(line)
            csv_file.writerow(get_row(line_contents, column_names))


def get_superset_of_column_names_from_file(json_file_path):
    column_names = set()
    with open(json_file_path) as fin:

        for line in fin:
            line_contents = json.loads(line)
        column_names.update(
            set(get_column_names(line_contents).keys())
            )
        return column_names


def get_column_names(line_contents, parent_key=''):
    column_names = []
    for k, v in line_contents.items():
        column_name = "{0}.{1}".format(parent_key, k) if parent_key else k
    if isinstance(v, collections.MutableMapping):
        column_names.extend(
                get_column_names(v, column_name).items()
                )
    else:
        column_names.append((column_name, v))
    return dict(column_names)


def get_nested_value(d, key):

    if '.' not in key:
        if key not in d:
            return None
    return d[key]
    base_key, sub_key = key.split('.', 1)
    if base_key not in d:
        return None
    sub_dict = d[base_key]
    return get_nested_value(sub_dict, sub_key)


def get_row(line_contents, column_names):
    row = []
    for column_name in column_names:
        line_value = get_nested_value(
            line_contents,
            column_name,
            )
    if isinstance(line_value, str):
        row.append('{0}'.format(line_value.encode('utf-8')))
    elif line_value is not None:
        row.append('{0}'.format(line_value))
    else:
        row.append('')
    return row

    if name == 'main':
        parser = argparse.ArgumentParser(
        description='Convert Yelp data from JSON format to CSV.',
        )

        parser.add_argument(
            'json_file',
            type=str,
            help='The json file to convert.',
            )

        args = parser.parse_args()

        json_file = args.json_file
        csv_file = '{0}.csv'.format(json_file.split('.json')[0])

        column_names = get_superset_of_column_names_from_file(json_file)
        read_and_write_file(json_file, csv_file, column_names)

这可能是一个愚蠢的问题（抱歉我不习惯python），但是我需要输入json路径，json文件名，csv路径吗？、csv 文件名等？如果是这样，正确的做法是什么？

非常感谢。

卡门

Answer 1

你的代码有问题的是下面这行

if name == 'main':

我认为是

if __name__ == '__main__':

所以，这是可能有效的代码。

import argparse
import collections
import csv
import json


def read_and_write_file(json_file_path, csv_file_path, column_names):
    with open(csv_file_path, 'w+') as fout:
        csv_file = csv.writer(fout)
    csv_file.writerow(list(column_names))
    with open(json_file_path, encoding="utf8") as fin:

        for line in fin:
            line_contents = json.loads(line)
            csv_file.writerow(get_row(line_contents, column_names))


def get_superset_of_column_names_from_file(json_file_path):
    column_names = set()
    with open(json_file_path) as fin:

        for line in fin:
            line_contents = json.loads(line)
        column_names.update(
            set(get_column_names(line_contents).keys())
            )
        return column_names


def get_column_names(line_contents, parent_key=''):
    column_names = []
    for k, v in line_contents.items():
        column_name = "{0}.{1}".format(parent_key, k) if parent_key else k
    if isinstance(v, collections.MutableMapping):
        column_names.extend(
                get_column_names(v, column_name).items()
                )
    else:
        column_names.append((column_name, v))
    return dict(column_names)


def get_nested_value(d, key):

    if '.' not in key:
        if key not in d:
            return None
    return d[key]
    base_key, sub_key = key.split('.', 1)
    if base_key not in d:
        return None
    sub_dict = d[base_key]
    return get_nested_value(sub_dict, sub_key)


def get_row(line_contents, column_names):
    row = []
    for column_name in column_names:
        line_value = get_nested_value(
            line_contents,
            column_name,
            )
    if isinstance(line_value, str):
        row.append('{0}'.format(line_value.encode('utf-8')))
    elif line_value is not None:
        row.append('{0}'.format(line_value))
    else:
        row.append('')
    return row

if __name__ == '__main__':
        parser = argparse.ArgumentParser(
        description='Convert Yelp data from JSON format to CSV.',
        )

        parser.add_argument(
            'json_file',
            type=str,
            help='The json file to convert.',
            )

        args = parser.parse_args()

        json_file = args.json_file
        csv_file = '{0}.csv'.format(json_file.split('.json')[0])

        column_names = get_superset_of_column_names_from_file(json_file)
        read_and_write_file(json_file, csv_file, column_names)

Yelp 数据集：Json 到 csv 转换器 (python 3)

Yelp dataset: Json to csv converter (python 3)

python

json

csv

python-3.6

yelp