How Do You Effectively Use Regular Expressions To Find Alliterative Expressions?

I have an assignment that requires me to use regular expressions in python to find alliterative expressions in a file that consists of a list of names. Here are the specific instru

Solution 1:

Please consider improving your question.

Especially the question is only useful for those who want to answer to the exactly the same question, which I think is almost no chance. Please think how to improve so that it can be generallized to the point where this QA can be helpful to others.

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I think your direction is about right.

• It's a good idea to check the input rightness using regular expression. r'[A-Z][a-z]* [A-Z][a-z]*' is a good expression.
• You can group the output by parentheses. So that you can easily get first and last name later on
• Keep in mind the difference between re.match and re.search. re.search(r'[A-Z][a-z]* [A-Z][a-z]*', 'aaRob Smith') returns a MatchObject. See this.

Also comment on general programming style

• Better to name variables first and last for readability, rather than k[0] and k[1] (and how is the letter k picked!?)

Here's one way to do:

import re

FULL_NAME_RE = re.compile(r'^([A-Z][a-z]*) ([A-Z][a-z]*)$')

defis_alliterative(name):
    """Returns True if it matches the alliterative requirement otherwise False"""# If not matches the name requirement, reject
    match = FULL_NAME_RE.match(name)
    ifnot match:
        returnFalse
    first, last = match.group(1, 2)
    first, last = first.lower(), last.lower()  # easy to assume all lower-casesif first[0] != last[0]:
        returnFalseif first[0] in'cst':  # Check sh/ch/th# Do special checkreturn _is_cst_h(first) == _is_cst_h(last)

    # All check passed!returnTruedef_is_cst_h(text):
    """Returns true if text is one of 'ch', 'sh', or 'th'."""# Bad (?) assumption that the first letter is c, s, or treturn text[1:].startswith('h')


names = [
    'Umesh Vazirani', 'Vijay Vazirani' , 'Barbara Liskov',
    'Leslie Lamport', 'Scott Shenker', 'R2D2 Rover', 'Shaq' , 'Sam Spade', 'Thomas Thing'
]
print [name for name in names if is_alliterative(name)]
# Ansprint ['Vijay Vazirani', 'Leslie Lamport', 'Sam Spade', 'Thomas Thing']

Solution 2:

Try this regular expression:

[a[0]forainre.findall('((?P<caps>[A-Z])[a-z]*\\s(?P=caps)[a-z]*)', names)]

Note: It does not handle the sh/ch/th special case.