python学习
dic = {'名字': '小明', '身高': 168, '体重': 55} print(dic['名字'] + '的身高是' + str(dic['身高']) + 'cm,' + '体重是' + str(dic['体重']) + 'kg.')
打印字典中的整形时记得转成字符串
# 定义空字典 dic = {} print(dic) # 添加键值对 dic['名字'] = '小明' dic['身高'] = 165 dic['体重'] = 55 # 打印字典 print(dic)
添加键值对
dic = {'名字': '小明', '身高': 168, '体重': 55} print(dic['名字'] + '的身高是' + str(dic['身高']) + 'cm,' + '体重是' + str(dic['体重']) + 'kg.') dic['身高'] = 178 dic['体重'] = 88 print(dic)
修改字典
dic = {'名字': '小明', '身高': 168, '体重': 55} print(dic) del dic['身高'] print(dic)
删除键值对
# 类似对象的同一属性组成字典 favorite_languages = { 'Lily': 'python', 'Tim': 'c', 'Tom': 'ruby', } print("Lily's favorite language is " + favorite_languages['Lily'].title() + ".")
多对象的同一属性 这样写,调用时直接写想知道的对象的名称,长print语句记得分行写
# 字典可能包含大量的数据,学会遍历字典 # for循环遍历 user_0 = { 'username': 'efermi', 'first': 'enrico', 'last': 'fermi', } for key, value in user_0.items(): print("\nKey: " + key) print("Value: " + value) # 方法.items()返回一个键值对列表,for循环一次将键和值存储到key 和 value中,然后打印 # 为了让键值更容易让人明白,将key 和value更换成具体名称 favorite_languages = { 'Lily': 'python', 'Tim': 'c', 'Tom': 'ruby', } for name, language in favorite_languages.items(): print(name.title() + "'s favorite language is " + language. Title())
for循环遍历字典
# 遍历字典的键,用方法keys() favorite_languages = { 'Lily': 'python', 'Tim': 'c', 'Tom': 'ruby', } for name in favorite_languages.keys(): print(name.title()) # 不使用.keys()也能输出一样的结果,因为遍历字典会默认遍历所有的键,用方法会更显式
遍历字典所有键
favorite_languages = { 'Lily': 'python', 'Tim': 'c', 'Tom': 'ruby', } friends = ['Lily', 'Tom'] for name in favorite_languages.keys(): print(name) if name in friends: # 如果name 在friends中 print(" Hi " + name + ", I see your favorite language is " + favorite_languages[name] + "!") if 'erin' not in favorite_languages.keys(): print("Erin,please take our poll!") print(favorite_languages.keys()) # keys()返回一个列表,包含在字典的所有键