Python标准库使用OrderedDict类的实例讲解

目标:创建一个字典,记录几对python词语,使用OrderedDict类来写,并按顺序输出。

写完报错:

[root@centos7 tmp]# python python_terms.py 
 File "python_terms.py", line 9
  from name,language in python_terms.items():
       ^
SyntaxError: invalid syntax

代码如下:

from collections import OrderedDict
python_terms = OrderedDict()
python_terms['key'] = 'vlaue'
python_terms['if']  = 'match'
python_terms['from'] = 'import'
from name,language in python_terms.items():
  print("python have many terms " + name.title() +
    language.title() + '.')
~   

结果for循环的for写成from了……总是出现简单的错误。

最终,正确代码如下:

from collections import OrderedDict
python_terms = OrderedDict()
python_terms['key'] = 'vlaue'
python_terms['if']  = 'match'
python_terms['from'] = 'import'
for name,language in python_terms.items():
  print("python have many terms " + name.title() +
    " " + language.title() + '.')

第一行,从模块collections中导入OrderedDict类;

第二行,创建了OrderedDict类的一个实例,并将其存储到python_terms中,也就是创建了一个空字典;

第三至五行,为字典添加键值对;

最后,循环输出结果。

运行结果:

[root@centos7 tmp]# python python_terms.py 
python have many terms Key Vlaue.
python have many terms If Match.
python have many terms From Import.

总结

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