In this assignment, you will write four functions that use regular expressions. For Problem 4, you need to rst download the Dodds et al happiness dictionary, happiness dictionary.py.
Instructions: Name your le hw4.py and submit on CCLE. Add comments to each function.
Problem 1:
Write a function mytype(v) that performs the same action as type(), and can recog-nize integers, oats, strings, and lists. Do this by rst using str(v), and then reading the string. Assume that lists can only contain numbers (not strings, other lists, etc...), and assume that strings can be anything that is not an integer, oat or list. Note that an empty list [] should also be recognized as a list.
Test cases:
mytype(10) and mytype(-10) should return "int"; mytype(-1.25) and mytype(10.0) should return "float"; mytype([1, 2, 3]) and mytype([]) should return "list"; mytype("abc") and mytype({1,2}) should return "string";
Problem 2:
Write a function findpdfs(L) that takes as input a list L of lenames (such as \IMG2309.jpg", \lecture1.pdf", \homework.py"), and returns a list of the names of all PDF les, without extension (\lecture1"). Assume that lenames may contain only letters and numbers.
Test case:
L = ["IMG2309.jpg", "lecture1.pdf", "homework.py", "homework2.pdf"] findpdfs(L) should return ["lecture1", "homework2"].
Problem 3:
Write a function findemail(url) that takes as input a URL, and outputs any email addresses that look like \xxx@xxx.xxx.xxx" with any number of dots after the @-sign on this page. The order of the email addresses in the output doesn’t matter. Your function should also get around tricks people use to hide their email addresses, such as
hangjie@math.ucla.edu
hangjie AT math DOT ucla DOT edu hangjie at math dot ucla dot edu hangjie[AT]ucla[DOT]edu hangjie[at]ucla[dot]edu
Test cases:
url1 = "https://www.math.ucla.edu/~hangjie/contact/"
url2 = "https://www.math.ucla.edu/~hangjie/teaching/Winter2019PIC16/regexTest"
findemail(url1) should return ["hangjie@math.ucla.edu"]; findemail(url2) should return ["hangjie1@math.ucla.edu", "hangjie2@math.ucla.edu", "hangjie3@math.ucla.edu",
"hangjie4@ucla.edu","hangjie5@ucla.edu","xxx@xxx.xxx.xxx"].
Problem 4:
Write a function happiness(text) that uses the Dodds et al [1] happiness dictionary to rate the happiness of a piece of english text (input as a single string). The happiness score is the average score over all words in the text that appear in the dictionary. For simplicity, you may neglect the words with special characters in the dictionary.
Test cases:
s1 = "Mary had a little lamb."
s2 = "Mary had a little lamb. Mary had a little lamb!" s3 = "A quick brown fox jumps over a lazy dog."
happiness(s1) and happiness(s2) should return 5.368; happiness(s3) should return 5.275.
References
[1] Peter Sheridan Dodds, Kameron Decker Harris, Isabel M Kloumann, Catherine A Bliss, and Christopher M Danforth. Temporal patterns of happiness and information in a global social network: Hedonometrics and twitter. PloS one, 6(12):e26752, 2011.
