Python 字典 : adding a value in a key already made without losing the original value

我正在尝试在字典中添加一个 xml 文件。现在我想做的是在不丢失值的情况下将值更新到字典中。这样做的原因是我想对 xml 文件进行分组以显示标记作者所做的所有更改。

这是 xml 文件的示例。

<log>  
<logentry  
revision="33185">  
<author>glv</author>  
<date>2012-08-06T21:01:52.494219Z</date>  
<paths>  
 
<path  
kind="file"  
action="M">/branches/Patch_4_2_0_Branch/text.xml</path>     
 
<path  
kind="dir"  
action="M">/branches/Patch_4_2_0_Branch</path>  
 
</paths>  
<msg>PATCH_BRANCH:N/A  
BUG_NUMBER:N/A  
FEATURE_AFFECTED:N/A  
OVERVIEW:N/A  
Adding the SVN log size requirement to the branch   
</msg>  
</logentry>  
 ....  
</log>  

这是我用 Python 编写的代码。

from xml.dom import minidom  
import smtplib  
from email.mime.text import MIMEText  
from datetime import datetime  
 
def xml_data ():  
 
f = open('C:\opidea_2.xml', 'r')  
 
data = f.read()  
 
f.close()  
 
dom = minidom.parseString(data)  
 
ic = (dom.getElementsByTagName('logentry'))  
 
dom = None        
content = ''  
author = {}    
for num in ic:  
 
authors = num.getElementsByTagName('author')  
 
if len(authors) > 0:  
 
  name = authors[0].firstChild.nodeValue  
 
  author.update({'author': str(name)})   
 
datef = []  
xmlDate = num.getElementsByTagName('date')[0].firstChild.nodeValue  
datef = [Good_Time]  
path_change = []   
paths = [x for x in num.getElementsByTagName("paths")[0].childNodes if isinstance(x, minidom.Element)]  
 
for path in paths:   
 
  x = path.childNodes[0].nodeValue    
 
if str(path.getAttribute("kind")) == 'dir':  
 
  path_change ='Directory location: ' + [str(x)]  
else:   
  path_change ='Filename: ' + [str(x)]  
 
xmlMsgf = []  
xmlMsg = num.getElementsByTagName('msg')  
 
 
if xmlMsg !='' and len(xmlMsg) > 0:  
  xmlMsgc = xmlMsg[0].firstChild.nodeValue  
  xmlMsgf = [xmlMsgc]  
 
 
 else:  
   xmlMsgc = "No comment made."  
   xmlMsgf = [xmlMsgc]  
 
 authorentry.push{('author',authorA),('date',datef),('path',path_change),('path',xmlMsgf))}            
 
    for k, v in [(authorentry)]: 
 
        try: 
 
            author[k].append(v) 
 
        except KeyError: 
 
            author[k] = [v] 
 
 author.update({'Date':datef,'Path':path_change,'msg':str(xmlMsgf)})  
 print author 
 
if __name__ == "__main__":  
  xml_data ()  

现在我想要的最终结果是这样的

Key 1 = glv , date1 ,path 1a path 1b , msg1 , date2 , path 2 , msg 2 , ...

key 2 = jsm, date1, path 1, msg 1.

我想将 author.update({'Date':datef,'Path':path_change,'msg':str(xmlMsgf)}) 分组以列出作者的 xml 文件以附加下一组内容作者做的。不太确定该怎么做。任何帮助，将不胜感激。这是我更新的代码，但我现在似乎收到了无效的语法错误:

  line 151 
    authorentry.push{('author',authorA),('date',datef),('path',path_change),('path',xmlMsgf))}            
                    ^ 
 SyntaxError: invalid syntax 

请您参考如下方法:

你不能在字典中“保留旧值”，每个键都有一个与之关联的值。

不过，您可以在字典中使用聚合值类型，例如，您可以使用列表作为值，并且每次您找到要添加的数据时，将其附加到关联列表中。

data = {} 
 
for k, v in [('a', 1), ('a', 2), ('b', 3)]: 
    try: 
        data[k].append(v) 
    except KeyError: 
        data[k] = [v]  # a list of one element! 

collections 模块中有一个方便的构造函数，可以使这更容易:

import collections 
 
data = collections.defaultdict(list) 
for k, v in [('a', 1), ('a', 2), ('b', 3)]: 
    data[k].append(v)