在Python中匹配列表和检测值变化之间的比较列表 [英] List of Dicts comparision to match between lists and detect value changes in Python

问题描述

我有一个从web服务调用返回的字典列表。

  listA = [{'name' ：'foo'，'val'：'x'}，
 {'name'：'bar'，'val'：'1'}，
 {'name'：'alice' val'：'2'}] 
  

我需要比较上次调用服务的结果并拉出更改。所以在下次调用时我可以得到：

  listB = [{'name'：'foo'，'val'：' y'}，
 {'name'：'bar'，'val'：'1'}，
 {'name'：'eve'，'val'：'z'}] $ b  

排序不保证，也不是列表的长度。名称不会改变。实际的数据有几个键，但我只关心'val'。

我试图找到一种方法来找回一个名字的列表

  changed = ['foo']＃或[{'name'：'foo'}] 
  

解决方案

我会建立一个辅助字典来存储 listA 的信息更明智：

  auxdict = dict（（d ['name']，d ['val']）for listA）
  

b $ b

那么任务变得很容易：

  changed = [d ['name'] for d in listB 
 if d ['name'] in auxdict and d ['val']！= auxdict [d ['name']]] 
  
I have a list of dictionaries that I get back from a web service call,
listA = [{'name':'foo', 'val':'x'}, 
         {'name':'bar', 'val':'1'},
         {'name':'alice','val':'2'}]
I need to compare the results from the previous call to the service and pull out changes. So on the next call I may get:
listB = [{'name':'foo', 'val':'y'},
         {'name':'bar', 'val':'1'},
         {'name':'eve','val':'z'}]
The ordering is not guaranteed and nor is the length of list. The names won't change. The actual data has several more keys, but I'm only concerned with 'val'.

I am trying to find a way to get back a list of the names that have had their values change between calls only for the names that are in both lists.
changed = ['foo'] # or [{'name':'foo'}]

解决方案
I'd build an auxiliary dict to store listA's information more sensibly:
auxdict = dict((d['name'], d['val']) for d in listA)
then the task becomes very easy:
changed = [d['name'] for d in listB 
           if d['name'] in auxdict and d['val'] != auxdict[d['name']]]


                        
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