昨天加班到深夜，所以隔了一天。

基于列表表示數據

bob = [['name', 'Bob Smith'], ['age', 42], ['pay', 10000]] sue = [['name', 'Sue Jones'], ['age', 45], ['pay', 20000]] people = [bob, sue] print(people) for person in people:print(person[0][1], person[2][1]) print([person[0][1] for person in people]) for person in people:print(person[0][1].split()[-1])person[2][1] *= 1.10 for person in people: print(person[2]) for person in people:for (name, value) in person:if name == 'name':print(value)# 定義一個函數還實現 def field(record, label):for (fname, fvalue) in record:if fname == label:return fvalueprint(field(bob, 'name'))

運行結果：

[[['name', 'Bob Smith'], ['age', 42], ['pay', 10000]], [['name', 'Sue Jones'], ['age', 45], ['pay', 20000]]] Bob Smith 10000 Sue Jones 20000 ['Bob Smith', 'Sue Jones'] Smith Jones ['pay', 11000.0] ['pay', 22000.0] Bob Smith Sue Jones Bob Smith

使用字典

字典為內建對象

import pprint # 使用字典表示記錄 bob = {'name': 'Bob Smith', 'age': 42, 'pay': 30000, 'job': 'dev'} sue = {'name': 'Sue Jones', 'age': 33, 'pay': 80000, 'job': 'pm'} print(bob['name'], sue['age']) # 其他建立字典的方法 bob2 = dict(name='Bob Smith', age=42) print(bob2) # 再換一種方法，一次一個字段的填寫字典 bob3 = {} bob3['name'] = 'Bob Three' print(bob3) # 使用Zip函數將name和value鏈接一起 names = ['name', 'age', 'pay'] values = ['Sue', 45, 20000] print(list(zip(names, values))) sue2 = dict(zip(names, values)) print(sue2) # 初始化空字典 fields = ('name', 'age', 'job') record = dict.fromkeys(fields, '?') print(record) # 使用字典 people = [bob, sue] for person in people:print(person['name'], person['age'], sep=',') names = [person['name'] for person in people] print('name:', names) print('list:', list(map((lambda x: x['name']), people))) print(sum(person['pay'] for person in people)) # 還可以使用類似SQL一樣的操作 print([rec['name'] for rec in people if rec['age'] >= 40]) print(3 ** 2) # 嵌套結構 bob4 = {'name': {'first': 'Bob', 'last': 'Smith'},'age': 42,'job': ['software', 'writing'],'pay': (4000, 50000) } print(bob4['name']) print(bob4['name']['last']) print(bob4['pay'][1]) for job in bob4['job']:print(job) bob4['job'].append('janitor') print('new job:', bob4['job']) db = {} db['bob'] = bob db['sue'] = sue print(db['bob']['name']) # 頂部引入了包 pprint.pprint(db) # 訪問所有對象，使用鍵索引 for key in db:print(key, '=>', db[key]['name']) # 使用迭代字典的值的集合 for rec in db.values():print(rec['pay']) x = [db[key]['name'] for key in db] print(x) y = [rec['name'] for rec in db.values()] print(y) db['tom'] = dict(name='Tom', age=50, job=None, pay=0) print(db['tom']) print("all keys", db.keys()) print('length of db', len(db))

運行結果

new job: ['software', 'writing', 'janitor'] Bob Smith {'bob': {'age': 42, 'job': 'dev', 'name': 'Bob Smith', 'pay': 30000},'sue': {'age': 33, 'job': 'pm', 'name': 'Sue Jones', 'pay': 80000}} bob => Bob Smith sue => Sue Jones 30000 80000 ['Bob Smith', 'Sue Jones'] ['Bob Smith', 'Sue Jones'] {'name': 'Tom', 'age': 50, 'job': None, 'pay': 0} all keys dict_keys(['bob', 'sue', 'tom']) length of db 3

所有的這些操作其實都在操作內存，雖然感覺和SQL很像

總結

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