Python:更改某些JSON数据并写入输出文件 [英] Python: Change certain JSON data and write to output file

问题描述

我正在尝试将.json文件解析为.kml文件，以供绘图程序使用.我将提供一组数据样本以简化此问题:

I am trying to parse a .json file into a .kml file to be used by a plotting program. I am going to give a set a data samples to simplify the issue:

我有一个LocationHistory.json文件，该文件具有以下结构:

I have a LocationHistory.json file that has the following structure:

{
 "data" : {
   "items" : [ {
     "kind" : "latitude#location",
     "timestampMs" : "1374870896803",
     "latitude" : 34.9482949,
     "longitude" : -85.3245474,
     "accuracy" : 2149
   }, {
     "kind" : "latitude#location",
     "timestampMs" : "1374870711762",
     "latitude" : 34.9857898,
     "longitude" : -85.3526902,
     "accuracy" : 2016"
   }]
  }
}

我定义了一个解析json数据的函数，然后将其馈入地标"字符串以写入(输出)到"location.kml"文件中:

I define a function that parses the json data and then I want to feed it into a "placemark" string to write (output) into a "location.kml" file:

import json
import datetime

def parse_jason_data_to_kml_file():
   kml_file = open('location.kml', "r+")

   #Here I parse the info inside the LocationHistory.json file
   json_file = open('LocationHistory.json')
   json_string = json_file.read()
   json_data = json.loads(json_string)

   locations = json_data["data"]["items"]

   # Next, I create a placemark string template:
   placemark = ["<Placemark>",
                "<TimeStamp><when>%(timestampMs)r</when></TimeStamp>",
                "<ExtendedData>",
                "<Data name=\"accuracy\">",
                "<value>%(accuracy)r</value>]",
                "</Data>",
                "</ExtendedData><Point><coordinates>%(longitude)r, %(latitude)r</coordinates></Point>",
                "</Placemark>"]
   placemark = "\n".join(placemark)

   # Now I loop through the json data and write the json data into the
   # placemark templete and write each placemark to a KML file.
   for location in locations:
       temp = placemark % location
       kml_file.write("\n" + temp + "\n")

   kml_file.close()
   json_file.close()

   parse_jason_data_to_kml_file()

此代码的目的是将包含.json数据的地标字符串从如下所示的地标字符串写入location.ml文件:

The aim of this code is to write the placemark string that contains the .json data, into the location.ml file, from the placemark string that looks like this:

<Placemark>
<TimeStamp><when>the "timestampMS" value from the JSON data item</when></TimeStamp>
<ExtendedData>
<Data name="accuracy">
<value> the "accuracy" value from the JSON data item </value>
</Data>
</ExtendedData><Point><coordinates>"longitude,latitude"</coordinates></Point>
</Placemark>

对于输出，应如下所示:

To an output, which should look like this:

<Placemark>
<TimeStamp><when>u'1374870896803'</when></TimeStamp>
<ExtendedData>
<Data name="accuracy">
<value>2149</value>
</Data>
</ExtendedData><Point><coordinates>-85.3245474,34.9482949</coordinates></Point>
</Placemark>

<Placemark>
<TimeStamp><when>u'1374870711762'</when></TimeStamp>
<ExtendedData>
<Data name="accuracy">
<value>2016</value>
</Data>
</ExtendedData><Point><coordinates>-85.3526902,34.9857898</coordinates></Point>
</Placemark>

一切正常，但是我的问题出在哪里，我需要从例如更改所有"timestampMs"信息(如LocationHistory.json文件中所示). 1374870896803至2013-07-26T10:24:24Z. 通过此代码，我可以将timestampMs作为日期时间对象打印出来:

All is working well as it should but my problem comes in where I need to change all the "timestampMs" info (as seen in LocationHistory.json file) from eg. 1374870896803 to eg. 2013-07-26T10:24:24Z. With this code I can print out the timestampMs as datetime objects:

for location in locations:
   print datetime.datetime.fromtimestamp(int(location.get("timestampMs"))/1000).strftime("%Y-%m-%dT%H:%M:%SZ")

因此，换句话说:我想将每个时间戳更改为如下形式:(注意顶部的日期时间为时间戳)

So in other words: I want to change each timestamp to look like this: (Notice the datetime on the top as the timestamp)

<Placemark>
<TimeStamp><when>2013-07-26T22:34:56Z</when></TimeStamp>
<ExtendedData>
<Data name="accuracy">
<value>2149</value>
</Data>
</ExtendedData><Point><coordinates>-85.3245474,34.9482949</coordinates></Point>
</Placemark>

谢谢

推荐答案

在for循环的开头添加一个步骤:

Add a step to the beginning of the for loop:

location['timestampMs'] = datetime.datetime.fromtimestamp(int(location.get("timestampMs"))/1000).strftime("%Y-%m-%dT%H:%M:%SZ")

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