Python基础练习100题 ( 51

昨天和大家分享了41-50题，今天继续来刷51~60题

Question 51:

Write a function to compute 5/0 and use try/except to catch the exceptions.

---

解法一

def divide():
    return 5/0

try:
    divide()
except ZeroDivisionError as ze:
    print("Why you are dividing a number by ZERO!!")
except:
    print("Any other exception")

Question 52:

Define a custom exception class which takes a string message as attribute.

---

解法一

class CustomException(Exception):
    """Exception raised for custom purpose
    Attributes:message -- explanation of the error
    """

    def __init__(self, message):
        self.message = message

num = int(input())
try:
    if num < 10:
        raise CustomException("Input is less than 10")
    elif num > 10:
        raise CustomException("Input is grater than 10")
except CustomException as ce:
    print("The error raised: " + ce.message)

Question 53:

Assuming that we have some email addresses in the "username@companyname.com" format, please write program to print the user name of a given email address. Both user names and company names are composed of letters only.

Example:
If the following email address is given as input to the
program:

john@google.com

Then, the output of the program should be:

john

In case of input data being supplied to the question, it should be assumed to be a console input.

---

解法一

def getname(s):
    try:
        return s.split("@")[0]
    except:
        print("This is not a email-adress")

getname("john@google.com")

解法二

import re

email = "john@google.com"
pattern = "(\w+)@\w+.com"
ans = re.findall(pattern,email)
print(ans)

Question 54:

Assuming that we have some email addresses in the "username@companyname.com" format, please write program to print the company name of a given email address. Both user names and company names are composed of letters only.

Example:
If the following email address is given as input to the program:

john@google.com

Then, the output of the program should be:

google

解法一

import re

email = "john@google.com"
pattern = "\w+@(\w+).com"
ans = re.findall(pattern,email)
print(ans)

解法二

def getname(s):
    try:
        return s.replace("@",".").split(".")[1]
    except:
        print("Something Wrong")

getname("john@google.com")

Question 55:

Write a program which accepts a sequence of words separated by whitespace as input to print the words composed of digits only.

Example:
If the following words is given as input to the program:

2 cats and 3 dogs.

Then, the output of the program should be:

['2', '3']

In case of input data being supplied to the question, it should be assumed to be a console input.

---

解法一

import re
s = input()
print(re.findall("\d+",s))

解法二

import re
s= input()
pattern = "\d+"
ans = re.findall(pattern,s)
print(ans)

解法三

[int(s) for s in input().split() if s.isdigit()]

Question 56:

Print a unicode string "hello world".

---

解法一

unicodeString = u"hello world!"
print(unicodeString)

Question 57:

Write a program to read an ASCII string and to convert it to a unicode string encoded by utf-8.

---

解法一

s = input()
u = s.encode('utf-8')
print(u)

Question 58:

Write a special comment to indicate a Python source code file is in unicode.

---

解法一

# -*- coding: utf-8 -*-

Question 59:

Write a program to compute 1/2+2/3+3/4+...+n/n+1 with a given n input by console (n>0).

*Example:
If the following n is given as input to the program:*

5

Then, the output of the program should be:

3.55

解法一

n = int(input())
sum = 0
for i in range(1, n+1):
    sum+= i/(i+1)
print(round(sum, 2))  # rounded to 2 decimal point

Question 60:

Write a program to compute:

f(n)=f(n-1)+100 when n>0
and f(0)=1

with a given n input by console (n>0).

Example:
If the following n is given as input to the program:

5

Then, the output of the program should be:

501

解法一

def f(n):
    if n == 0:
        return 1
    else:
        return f(n-1) + 100

n = int(input())
print(f(n))

这十道题的代码在我的github上，如果大家想看一下每道题的输出结果，可以点击以下链接下载：

• Python 51-60题

我的运行环境Python 3.6+,如果你用的是Python 2.7版本，绝大多数不同就体现在以下3点：

• raw_input()在Python3中是input()
• print需要加括号
• fstring可以换成.format(),或者%s，%d

谢谢大家，我们下期见！希望各位朋友不要吝啬，把每道题的更高效的解法写在评论里，我们一起进步！！！