技術標籤：Python_Basepython

簡介

字典是一種可變容器模型，且可儲存任意型別物件，字典的每個鍵值 key=>value對用冒號:分割，每個鍵值對之間用逗號 ,分割，整個字典包括在花括號{}中 ，如：

object = {
	'color': 'yellow', 
	'size': 'big'
}
print(object['color'])
print(object['size'])

新增鍵值對

object['age'] = 18
object['sex'] = 'man'
print(object)

建立一個空字典

object = {}
object['color'] = 'yellow'
object['size'] = 'big'
print(object)
 

修改字典中的值

object['color'] = 'black'
print(object)

刪除鍵值對

object = {'color': 'black', 'age': 18}
del object['color']
print(object)

遍歷鍵值對

user = {
	'username': 'coisini',
	'age': '18',
	'sex': 'man'
}
for key,value in user.items():
	print('key:' + key)
	print('value:' + value)

遍歷所有鍵值

use_languages = {
	'one_user': 'python',
	'two_user': 'c',
	'three_user': 'ruby',
	'four_user': 'python'
}
for key in use_languages.keys():
	print('key:' + key)
	print('value:' + use_languages[key])
	
	if key == 'one_user':
		print('one_user is in use_languages')
 

use_languages.key() 簡寫為use_languages

if 'four_user' in use_languages:
	print('four_user is in use_languages')

順序遍歷所有鍵值

for name in sorted(use_languages.keys()):
	print(name.title())

遍歷字典中的所有值

for language in use_languages.values():
	print(language.title())

使用集合（set）剔除重複項

for language in set(use_languages.values()):
	print(language.title())
 

列表字典巢狀

one_user = {'color': 'black', 'age': 5}
two_user = {'color': 'white', 'age': 10}
three_user = {'color': 'yellow', 'age': 15}

users = [one_user, two_user, three_user]
for user in users:
	print(user)

字典列表巢狀

user = {
	'username': 'coisini',
	'languages': ['Java', 'Python']
}
	
for language in user['languages']:
	print('\t' + language)

字典字典巢狀

users = {
	'coisini': {
		'name': 'coisini',
		'age': 18,
		'location': 'China'
	},
	'maggieq': {
		'name': 'maggieq',
		'age': '22',
		'location': 'Canada'
	}
}

for username, userinfo in users.items():
	print('\nusername:' + username)
	
	for key, val in users[username].items():
		print('\tkey:' + str(key))
		print('\tval:' + str(val))