遍歷字典鍵

1. 使用 items() 可以遍歷 (traverse) 字典的鍵及值，若只想遍歷字典的鍵，可用如下 keys()：

   for key in dict_name.keys():
   

2. 範例：遍歷並列出字典 uid 的鍵。

   pyuser@deyu:~/zzz$ cat dict7.py
   #!/usr/bin/python
   
   uid = { 'dywang':1000, 'david':2346, 'linda':1324 }
   for key in uid.keys():
   	print("key = %s" % key)
   

3. 執行結果

   pyuser@deyu:~/zzz$ ./dict7.py
   key = dywang
   key = david
   key = linda