Python学习之旅 读书笔记系列
Day 15
《Python编程从入门到实践》
复盘：第一部分基础知识（第1章~11章）
练习题
第6章 字典
认识字典及其处理方式
1.my_friends.py
初识字典及字典的键-值获取
my_friend = {
"first_name":"zou","last_name":"jie",
"age":"32","city":"shenzhen",
}
#注意冒号在键跟值中间,分行时左右花括号的位置，以及养成习惯最后一组预留”,“
print(my_friend["first_name"])
print(my_friend["city"].upper())
print(my_friend["last_name"].title())
favorite_number = {}
favorite_number["Jie_zou"] = 8
favorite_number["Wedny_tu"] = 9
favorite_number["Jason_zou"] = 5
favorite_number["Smile_zou"] = 6
favorite_number["Eric_liu"] = 3
print("Jie_zou's favorite number is " + str(favorite_number["Jie_zou"]) + ".")
print("Smile_zou's favorite number is " +
str(favorite_number["Smile_zou"]) + ".")
#打印时断行，在合适地方分拆
word_list = {}
word_list["print"] = "打印"
word_list["while"] = "循环"
word_list["if"] = "条件判断"
word_list["range"] = "列表"
word_list["tuple"] = "元组"
print("print:" + word_list["print"])
print("\nwhile:" + word_list["while"])
print("range:" + word_list["range"])
#特别留意换行符在冒号内,且放在换行行的句前
输出结果如下：
2.word_list.py
字典的遍历：键-值对，键，值
word_list = {}
word_list["print"] = "打印"
word_list["while"] = "循环"
word_list["if"] = "条件判断"
word_list["range"] = "列表"
word_list["tuple"] = "元组"
for word, mean in word_list.items():
"""遍历字典中的键-值对"""
print("\nWord:" + word)
print("Mean:" + mean)
word_list["sort"] = "排序"
word_list["len"] = "字段长度"
word_list["strip"] = "去除空格"
word_list["string"] = "字符串"
word_list["python_zen"] = "Python之禅"
for word, mean in word_list.items():
"""添加5组数据之后，再遍历字典中的键-值对"""
print("\nWord:" + word)
print("Mean:" + mean)
river_list = {}
river_list["nile"] = "egypt"
river_list["changjiang"] = "china"
river_list["amazon"] = "america"
for river,country in river_list.items():
"""一起提取键-值对中的键和值, items后面不要忘记括号"""
print("\nThe " + river.title() + "runs through " + country.title() + ".")
for river in river_list.keys():
"""key,value后面记得加s"""
print("\n" + river)
for country in river_list.values():
print("\n" + country.title())
输出结果如下：
3.favorite_languages.py
字典与列表的综合运用，范围和条件判断
favorite_languages = {
'jen':'python',
'sarah':'c',
'edward':'ruby',
'phil':'python',
}
survey_list = [
'jen','sarah',
'jason','edward',
'smile','phil'
]
for name in survey_list:
"""嵌套时，注意字典范围和判断的先后，keys后面小括号不要忘记"""
if name in favorite_languages.keys():
print('Thanks for your support!')
else:
print('Please help to intend the survey!')
输出结果如下：
其他
- 感受及注意事项
- 如果多行定义字典时，先输左花括号，下一行记得“缩进4个空格并以逗号结尾”，最后一行结尾时仍然加上“，”为添加键-值做准备
- 打印时分行，记得在合适的地方拆分，末尾加上拼接符（+）
- 遍历时：.item()为键-值对，.keys()为键，.values()为值，要剔除重复值时加上集合set(字典.values())
