上一篇文章中提到了学习编程练习的重要性，今天就通过几个练习题，来巩固一下Python中几个重要的技能。
将字典中大于2的值过滤掉。
#Filter out values of equal or greater than 2#Note that for Python 2 you will have to use iteritemsd = {"a": 1, "b": 2, "c": 3}读取输入的一句话中的单词数。
a,b 中的对应数字想加并输出结果。
#Print out in each line the sum of homologous items from the two sequencesa = [1, 2, 3] b = (4, 5, 6)
发现下面代码中的错误。
#Please fix the script so that it returns the user submited first name for the first %s#and the second name for the second %sfirstname = input("Enter first name: ")
secondname = input("Enter second name: ")print("Your first name is %s and your second name is %s" % firstname, secondname)打印出第三个“employee”的“LastName”,并添加一个“Albert Bert”的"employee"
d = {"employees":[{"firstName": "John", "lastName": "Doe"},
{"firstName": "Anna", "lastName": "Smith"},
{"firstName": "Peter", "lastName": "Jones"}],"owners":[{"firstName": "Jack", "lastName": "Petter"},
{"firstName": "Jessy", "lastName": "Petter"}]}打印a中的index 和 item 输出格式如下
Item 1 has index 0
Item 2 has index 1
Item 3 has index 2
a = [1, 2, 3]
在字母数字和符号中选6个字符，随机生成6位的密码。
要求用户输入用户名和密码，用户名不能与数据库中(database["Mercury", "Venus","Earth","Mars", "Jupiter", "Saturn", "Uranus", "Neptune", "Pluto"])重复，密码必须大于5位，并且包含数字和大写字母。
以上题目节选自udemy上的课程
答案如下：
1.将字典中大于2的值过滤掉
d = {"a": 1, "b": 2, "c": 3}
d = dict((key,value) for key, value in d.items() if value<3)这个题目有几个重要的点：(1). 遍历字典格式的数据需要，d.items().
(2). 这种重构的语句在Python中非常常见。同样的我们也可以输出一个小于3的list：a = list(key for key, value in d.items() if value<3)
读取输入的一句话中的单词数。
s = input('Please enter: ')
s_list = s.split(' ')
len(s_list)这个题目几个重点：(1). 处理String中的几个非常常见的方法，如.split(), .strip() 等等。(2). len() size() type() 等Python常见的的方法。
a,b 中的对应数字想加并输出结果
a = [1, 2, 3] b = (4, 5, 6)print(list(i+j for i,j in zip(a,b)))
zip的使用，非常重要.
正确的答案如下
firstname = input("Enter first name: ")
secondname = input("Enter second name: ")print("Your first name is %s and your second name is %s" % (firstname, secondname))在Python中有多个格式输出的时候需要用元组（加括号）的形式
打印出第三个“employee”的“LastName”,并添加一个“Albert Bert”的"employee"
d = {"employees":[{"firstName": "John", "lastName": "Doe"},
{"firstName": "Anna", "lastName": "Smith"},
{"firstName": "Peter", "lastName": "Jones"}],"owners":[{"firstName": "Jack", "lastName": "Petter"},
{"firstName": "Jessy", "lastName": "Petter"}]}print(d["employees"][2]["firstName"])
d["employees"].append({"firstName": "Albert", "lastName": "Bert"})这道题的关键是找出d的结构，这是一个字典嵌套list再嵌套字典的结构。
打印a中的index 和 item 输出格式如下
Item 1 has index 0
Item 2 has index 1
Item 3 has index 2
a = [1, 2, 3]for index, item in enumerate(a): print("Item s% has index s%\n"%(item, index))枚举enumerate 的应用，非常重要更多例子见(这里)[http://book.pythontips.com/en/latest/enumerate.html]
在字母数字和符号中选6个字符，随机生成6位的密码
import ramdon
characters = "abcdefghijklmnopqrstuvwxyz01234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ!@#$%^&*()?"chosen = ramdon.sample("characters",6)
password = "".join(chosen)这个题目有两个知识点，(1). ramdon,这个Python自带的重要库，已经random.sample()的使用方法。(2). string.joint()这个方法。
要求用户输入用户名和密码，用户名不能与数据库中(database["Mercury", "Venus","Earth","Mars", "Jupiter", "Saturn", "Uranus", "Neptune", "Pluto"])重复，密码必须大于5位，并且包含数字和大写字母。
database = ["Mercury", "Venus","Earth","Mars", "Jupiter", "Saturn", "Uranus", "Neptune", "Pluto"]while True:
user_name = input("Please enter your user name: ") if user_name in database:
print("The user name is exits, please try again!") else: breakwhile True:
error_msg = []
psw = input("Please enter your password: ") if len(psw)<6:
error_msg.append( "Password must over 5 characters.") if not any(i.isdigit() for i in psw):
error_msg.append("Password must contain at lease one number") if not any(i.isupper() for i in psw):
error_msg.append("Password must contain at least one uppercase letter") if len(error_msg) > 0: for i in error_msg:
print(i) else: break这道题有这么几个知识点： (1). while 循环语句的使用。(2). if .... in .... 的使用。(3). i.isdigit() 和 i.isupper() 方法的使用。(4). any()的使用。
作者：Hongtao洪滔
链接：https://www.jianshu.com/p/3bbf3664a65f