Python：从文件夹中读取多个json文件

Question

我想知道如何json从单个文件夹中读取多个文件（无需指定文件名，只是它们是json文件）。

另外，有可能将它们转换为pandasDataFrame吗？

能给我一个基本的例子吗？

Answer 1

一种选择是使用os.listdir列出目录中的所有文件，然后仅查找以’.json’结尾的文件：

import os, json
import pandas as pd

path_to_json = 'somedir/'
json_files = [pos_json for pos_json in os.listdir(path_to_json) if pos_json.endswith('.json')]
print(json_files)  # for me this prints ['foo.json']

现在，您可以使用pandas DataFrame.from_dict将json（此时为python字典）读入pandas数据帧：

montreal_json = pd.DataFrame.from_dict(many_jsons[0])
print montreal_json['features'][0]['geometry']

印刷品：

{u'type': u'Point', u'coordinates': [-73.6051013, 45.5115944]}

在这种情况下，我将一些json附加到列表中many_jsons。我列表中的第一个json实际上是一个geojson，其中包含蒙特利尔的一些地理数据。我已经很熟悉内容了，所以我打印出了“几何图形”，这让我对蒙特利尔感到满意。

以下代码总结了以上所有内容：

import os, json
import pandas as pd

# this finds our json files
path_to_json = 'json/'
json_files = [pos_json for pos_json in os.listdir(path_to_json) if pos_json.endswith('.json')]

# here I define my pandas Dataframe with the columns I want to get from the json
jsons_data = pd.DataFrame(columns=['country', 'city', 'long/lat'])

# we need both the json and an index number so use enumerate()
for index, js in enumerate(json_files):
    with open(os.path.join(path_to_json, js)) as json_file:
        json_text = json.load(json_file)

        # here you need to know the layout of your json and each json has to have
        # the same structure (obviously not the structure I have here)
        country = json_text['features'][0]['properties']['country']
        city = json_text['features'][0]['properties']['name']
        lonlat = json_text['features'][0]['geometry']['coordinates']
        # here I push a list of data into a pandas DataFrame at row given by 'index'
        jsons_data.loc[index] = [country, city, lonlat]

# now that we have the pertinent json data in our DataFrame let's look at it
print(jsons_data)

对我来说，这印：

  country           city                   long/lat
0  Canada  Montreal city  [-73.6051013, 45.5115944]
1  Canada        Toronto  [-79.3849008, 43.6529206]

了解此代码对于在目录名称“ json”中有两个geojsons可能会有所帮助。每个json具有以下结构：

{"features":
[{"properties":
{"osm_key":"boundary","extent":
[-73.9729016,45.7047897,-73.4734865,45.4100756],
"name":"Montreal city","state":"Quebec","osm_id":1634158,
"osm_type":"R","osm_value":"administrative","country":"Canada"},
"type":"Feature","geometry":
{"type":"Point","coordinates":
[-73.6051013,45.5115944]}}],
"type":"FeatureCollection"}