CS50-Python实验3，4
Week3 Exceptions
Fuel Gauge
题目描述：
输入分数字符串，判断并输出相应的百分数；特例不足1%输出E,超出99%输出F
思路：
1，从字符串中取出x,y；
2，按题中要求计算输出；
题解：
while True:
try:
## 取出x,y
x, z, y= input("Fraction: ")
x, y = int(x), int (y)
##防止出错
if y == 0:
raise ZeroDivisionError
if x > y:
raise ValueError
break
except(ValueError, ZeroDivisionError):
pass
## 模拟题
if 0 < x/y < 0.99:
print(f"{round(x/y*100)}%")
elif x/y >= 0.99:
print("F")
else:
print("E")
Felipe’s Taqueria
题目描述：
根据用户输入的信息，匹配菜单价格，最终算出最终价格。
题解：
## 菜单信息
menu = {
"Baja Taco": 4.00,
"Burrito": 7.50,
"Bowl": 8.50,
"Nachos": 11.00,
"Quesadilla": 8.50,
"Super Burrito": 8.50,
"Super Quesadilla": 9.50,
"Taco": 3.00,
"Tortilla Salad": 8.00,
}
##total：结果
total = 0
## 计算输出
while True:
try:
## title(): 首字母大写其余小写
item = input("Item: ").title()
if item in menu:
total += menu[item]
print(f"Total: ${total:.2f}")
except EOFError:
print()
break
Grocery List
题目描述：
记录用户输入商品，最终输出已输入的商品以及商品数量；
题解：
## 存储商品信息
list = {}
while True:
## 输入处理
try:
## upper():字符串大写
item = input("").upper()
except EOFError:
print()
break
## 记录商品
if item in list:
list[item] += 1
else:
list[item] = 1
## 输出结果
for item, cnt in sorted(list.items()):
print(f"{cnt} {item}")
Outdated
题目描述：
用户输入9/8/1636，September 8, 1636形式，系统转换输出1636-09-08；若用户输出其他形式抛异常。
题解：
## 月份记录
months = [
"January",
"February",
"March",
"April",
"May",
"June",
"July",
"August",
"September",
"October",
"November",
"December"
]
##思路：分情况讨论
while True:
date = input("Date: ")
month,day,year = "", "", ""
try:
## 9/8/1636
if len(date.split("/")) == 3:
date = date.split("/")
month, day, year = map(int, date)
## September 8, 1636
else:
date = date.split(",")
if len(date) == 2:
month, day = date[0].split()
month = months.index(month)+1
day, year = int(day), int(date[1])
##输出
if 1<=int(month)<=12 and 1<=int(day)<=31:
print(f"{year:04}-{month:02}-{day:02}")
break
except ValueError:
pass
Week4 Libraries
Emojize
题目描述：
练习python调用库操作；
题解：
from emoji import emojize
print("Output:", emojize(input("Input: ")))
Frank, Ian and Glen’s Letters
题目描述：
The documentation for pyfiglet isn’t very clear, but you can use the module as follows:
from pyfiglet import Figlet
figlet = Figlet()
You can then get a list of available fonts with code like this:
figlet.getFonts()
You can set the font with code like this, wherein f is the font’s name as a str:
figlet.setFont(font=f)
And you can output text in that font with code like this, wherein s is that text as a str:
print(figlet.renderText(s))
题解：
from pyfiglet import Figlet
import random
import sys
fonts = Figlet().getFonts()
# Zero if the user would like to output text in a random font.
# Two if the user would like to output text in a specific font, in which case the first of the two should be -f or --font, and the second of the two should be the name of the font.
if len(sys.argv) == 1:
font = random.choice(fonts)
elif len(sys.argv) == 3:
if sys.argv[1] in ["-f", "--font"] and sys.argv[2] in fonts:
font = sys.argv[2]
else:
sys.exit("Invalid arguments.")
else:
sys.exit("Invalid number of arguments.")
## 输出
text = input("Input: ")
print("Output:\n", Figlet(font=font).renderText(text))
Adieu, Adieu
题目描述：
用户输入名字，将所有名字按照inflect中的操作输出；
题解：
import inflect
p = inflect.engine()
names = []
while True:
try:
names.append(input("Name: ").strip())
except EOFError:
print()
break
print(f"Adieu, adieu, to {p.join(names)}")
Guessing Game
题目描述：
用户选择猜数等级，然后进行竞猜。竞猜过程中会提示用户信息，直到猜中为止；
题解：
from random import randint
## 选择猜数等级
while True:
try:
n = int(input("Level: "))
if n < 0:
raise ValueError
break
except ValueError:
pass
## 生成竞猜的数
rand = randint(1, n)
## 用户判断
while True:
try:
guess = int(input("Guess: "))
if guess < rand:
print("Too small!")
elif guess > rand:
print("Too large!")
else:
print("Just right!")
break
except ValueError:
pass
Little Professor
题目描述：
用户选择等级进行随机式子生成，最后根据算式正确结果算取所得分数；
题解：
import random
def main():
level = get_level()
score = 0
for _ in range(10):
x = generate_integer(level)
y = generate_integer(level)
## 计算score
tries = 0
while tries < 3:
try:
tries += 1
answer = int(input(f"{x} + {y} = "))
if answer == x+y:
score += 1
break
else:
print("EEE")
except ValueError:
pass
print(f"{x} + {y} = {x+y}")
print("Score", score)
## 获取等级
def get_level():
while True:
try:
level = int(input("Level: "))
if level in [1, 2, 3]:
return level
except ValueError:
pass
## 在范围内生成数字
def generate_integer(level):
if level == 1:
return random.randint(0, 9)
return random.randint(10 ** (level - 1), 10**level - 1)
if __name__ == "__main__":
main()
Bitcoin Price Index
题目描述：
Expects the user to specify as a command-line argument the number of Bitcoins n, that they would like to buy. If that argument cannot be converted to a float, the program should exit via sys.exit with an error message.
Queries the API for the CoinDesk Bitcoin Price Index at https://api.coindesk.com/v1/bpi/currentprice.json, which returns a JSON object, among whose nested keys is the current price of Bitcoin as a float. Be sure to catch any exceptions, as with code like:
import requests
try:
...
except requests.RequestException:
...
Outputs the current cost of Bitcoins in USD to four decimal places, using , as a thousands separator.
题解：
import sys
import requests
try:
response = requests.get("https://api.coindesk.com/v1/bpi/currentprice.json")
data = response.json()
current_price = data["bpi"]["USD"]["rate_float"]
except requests.RequestException:
sys.exit()
try:
n = float(sys.argv[1])
except IndexError:
sys.exit("Missing command-line argument")
except ValueError:
sys.exit("Command-line argument is not a number")
print(f"${n * current_price:,.4f}")