Python-51~55

---51---

 Question:

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

Solution:

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---52---

Question：

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

Solution:

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---53---

Question:

>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

Hints:

>Use \w to match letters.

Solution:

解法一

解法二

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---54---

Question：

>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

Solution:

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---55---

Question:

>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']

Hints:

>Use re.findall() to find all substring using regex.

Solution:

解法一

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解法二

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