Python:从文件夹中读取多个json文件
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pandas
DataFrame吗?
能给我一个基本的例子吗?
回答:
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, jsonimport 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, jsonimport 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/lat0 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"}
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