>[info] 程序中，大多數的參數都以字典的形式存儲。 [TOC] <br> ### 字典的定義 字典dictionary是一種以key-value鍵值對的形式存儲數據，key是不可變的，可以是字符串，數字或元組，而value可以是任意一種數據類型。 #### 字典的賦值 ```python person={'name':'Milton','age':18,'hobby':['basketball','football']} ``` #### 字典的讀取 ```cmd >>> person={'name':'Milton','age':18,'hobby':['basketball','football']} >>> person['name'] 'Milton' ``` #### 字典值的修改 ```cmd >>> person={'name':'Milton','age':18,'hobby':['basketball','football']} >>> person['name']='Cherish' >>> person {'name': 'Cherish', 'age': 18, 'hobby': ['basketball', 'football']} ``` ### 字典常用方法 #### clear():清除字典中所有元素 ```cmd >>> person={'name':'Milton','age':18,'hobby':['basketball','football']} >>> person {'name': 'Milton', 'age': 18, 'hobby': ['basketball', 'football']} >>> person.clear() >>> person {} ``` #### copy():淺拷貝 ```cmd >>> person={'name':'Milton','age':18,'hobby':['basketball','football']} >>> person2=person.copy() >>> person2 {'name': 'Milton', 'age': 18, 'hobby': ['basketball', 'football']} >>> person['name']='Cherish' >>> person {'name': 'Cherish', 'age': 18, 'hobby': ['basketball', 'football']} >>> person2 {'name': 'Milton', 'age': 18, 'hobby': ['basketball', 'football']} >>> ``` 注意區分copy()與`=`賦值的區別，慎用`=` ```cmd >>> person={'name':'Milton','age':18,'hobby':['basketball','football']} >>> person2=person >>> person['name']='Cherish' >>> person {'name': 'Cherish', 'age': 18, 'hobby': ['basketball', 'football']} >>> person2 {'name': 'Cherish', 'age': 18, 'hobby': ['basketball', 'football']} ``` #### dict.fromkeys(seq[, value]):以一個序列中的值作為key，創建字典 ```cmd >>> person=['Milton','Cherish'] >>> detail=dict.fromkeys(person,{'sex':'M'}) >>> detail {'Milton': {'sex': 'M'}, 'Cherish': {'sex': 'M'}} ``` #### get(k, d=None):根據key，獲取元素值 ```cmd >>> person={'name':'Milton','age':18,'hobby':['basketball','football']} >>> person.get('name') 'Milton' >>> person.get('score',99) 99 ``` #### items():以列表返回可遍歷的(鍵, 值) 元組數組 ```cmd >>> person={'name':'Milton','age':18,'hobby':['basketball','football']} >>> person.items() dict_items([('name', 'Milton'), ('age', 18), ('hobby', ['basketball', 'football'])]) >>> ``` #### keys():以列表返回所有的key ```cmd >>> person={'name':'Milton','age':18,'hobby':['basketball','football']} >>> person.keys() dict_keys(['name', 'age', 'hobby']) >>> ``` #### values():以列表返回字典中的所有值 ```cmd >>> person={'name':'Milton','age':18,'hobby':['basketball','football']} >>> person.values() dict_values(['Milton', 18, ['basketball', 'football']]) ``` #### pop(k, d=None):刪除key所對應的值，返回被刪除的值。 key值必須給出。 否則，返回default值。 ```cmd >>> person={'name':'Milton','age':18,'hobby':['basketball','football']} >>> person.pop('age') 18 >>> person {'name': 'Milton', 'hobby': ['basketball', 'football']} >>> ``` #### popitem():隨機返回并刪除字典中的一對鍵和值。 ```cmd >>> person={'name':'Milton','age':18,'hobby':['basketball','football']} >>> person.popitem() ('hobby', ['basketball', 'football']) >>> person {'name': 'Milton', 'age': 18} ``` #### setdefault(self, k, d=None):設置默認值 如果對應的key不存在，則修改字典，并返回設置的默認值 如果對應的key存在，則不修改字典，直接返回原來的值 ```cmd >>> person={'name':'Milton','age':18,'hobby':['basketball','football']} >>> person.setdefault('name','Cherish') 'Milton' >>> person {'name': 'Milton', 'age': 18, 'hobby': ['basketball', 'football']} >>> person.setdefault('sex','M') 'M' >>> person {'name': 'Milton', 'age': 18, 'hobby': ['basketball', 'football'], 'sex': 'M'} ``` #### update(self, E=None, **F):用一個字典更新當前字典 ```cmd >>> person={'name':'Milton','age':18,'hobby':['basketball','football']} >>> person.update({'name':'Cherish','sex':'female'}) >>> person {'name': 'Cherish', 'age': 18, 'hobby': ['basketball', 'football'], 'sex': 'female'} ``` <hr style="margin-top:100px"> :-:  ***微信掃一掃，關注“python測試開發圈”，了解更多測試教程！***