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Outdated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}")

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