Exercises¶

Has Vowels¶

Create a function has_vowel, that accepts a string and returns True if the string contains a vowel (a, e, i, o, or u) returns False otherwise.

Your function should work like this:

>>> has_vowel("rhythm")
False
>>> has_vowel("exit")
True

Is Integer¶

Create a function is_integer that accepts a string and returns True if the string represents an integer.

By our definition, an integer:

• Consists of 1 or more digits
• May optionally begin with -
• Does not contain any other non-digit characters.

Your function should work like this:

>>> is_integer("")
False
>>> is_integer(" 5")
False
>>> is_integer("5000")
True
>>> is_integer("-999")
True
>>> is_integer("+999")
False
>>> is_integer("00")
True
>>> is_integer("0.0")
False

Is Fraction¶

Create a function is_fraction that accepts a string and returns True if the string represents a fraction.

By our definition a fraction consists of:

1. An optional - character
2. Followed by 1 or more digits
3. Followed by a /
4. Followed by 1 or more digits, at least one of which is non-zero (the denominator cannot be the number 0).

Your function should work like this:

>>> is_fraction("")
False
>>> is_fraction("5000")
False
>>> is_fraction("-999/1")
True
>>> is_fraction("+999/1")
False
>>> is_fraction("00/1")
True
>>> is_fraction("/5")
False
>>> is_fraction("5/0")
False
>>> is_fraction("5/010")
True
>>> is_fraction("5/105")
True
>>> is_fraction("5 / 1")
False

Get File Extension¶

Make a function that accepts a full file path and returns the file extension.

Example usage:

>>> get_extension('archive.zip')
'zip'
>>> get_extension('image.jpeg')
'jpeg'
>>> get_extension('index.xhtml')
'xhtml'
>>> get_extension('archive.tar.gz')
'gz'

Hexadecimal Words¶

Find every word that consists solely of the letters A, B, C, D, E, and F.

Examples: decaf, bead, cab

Tetravocalic¶

Find all words that include four consecutive vowels.

Hexaconsonantal¶

Find at least one word with 6 consecutive consonants. For this problem treat y as a vowel.

Crossword Helper¶

Make a function possible_words that accepts a partial word with underscores representing missing letters and returns a list of all possible matches.

Use your crossword helper function to solve the following:

1. water tank: CIS____
2. pastry: ___TE
3. temporary: __A_S_E__

Repeat Letter¶

Find every word with 5 repeat letters.

Decimal Numbers¶

Write a function to match decimal numbers.

We want to allow an optional - and we want to match numbers with or without one decimal point.

Example usage:

>>> is_number("5")
True
>>> is_number("5.")
True
>>> is_number(".5.")
False
>>> is_number(".5")
True
>>> is_number("01.5")
True
>>> is_number("-123.859")
True
>>> is_number("-123.859.")
False
>>> is_number(".")
False

Abbreviate¶

Make a function that creates an acronym from a phrase.

Example usage:

>>> abbreviate('Graphics Interchange Format')
'GIF'
>>> abbreviate('frequently asked questions')
'FAQ'
>>> abbreviate('cascading style sheets')
'CSS'
>>> abbreviate('Joint Photographic Experts Group')
'JPEG'
>>> abbreviate('content management system')
'CMS'
>>> abbreviate('JavaScript Object Notation')
'JSON'
>>> abbreviate('HyperText Markup Language')
'HTML'

Hex Colors¶

Write a function to match hexadecimal color codes. Hex color codes consist of an octothorpe symbol followed by either 3 or 6 hexadecimal digits (that’s 0 to 9 or a to f).

Example usage:

>>> is_hex_color("#639")
True
>>> is_hex_color("#6349")
False
>>> is_hex_color("#63459")
False
>>> is_hex_color("#634569")
True
>>> is_hex_color("#663399")
True
>>> is_hex_color("#000000")
True
>>> is_hex_color("#00")
False
>>> is_hex_color("#FFffFF")
True
>>> is_hex_color("#decaff")
True
>>> is_hex_color("#decafz")
False

Valid Date¶

Create a function that returns True if given a date in YYYY-MM-DD format.

For this exercise we’re more worried about accepting valid dates than we are about excluding invalid dates.

A regular expression is often used as a first wave of validation. Complete validation of dates should be done in our code outside of regular expressions.

Example usage:

>>> is_valid_date("2016-01-02")
True
>>> is_valid_date("1900-01-01")
True
>>> is_valid_date("2016-02-99")
False
>>> is_valid_date("20-02-20")
False
>>> is_valid_date("1980-30-05")
False

Palindromes¶

Using the dictionary file, find all five letter palindromes.

Double Double¶

Find all words that have a consecutive repeated letter two times with only one other letter between them.

For example, these words should be matched:

• freebee
• assessed
• voodoo

Repetitive Words¶

Find all words that consist of the same letters repeated two times.

Examples:

• tutu
• cancan
• murmur

Normalize JPEG Extension¶

Make a function that accepts a JPEG filename and returns a new filename with jpg lowercased without an e.

Example usage:

>>> normalize_jpeg('avatar.jpeg')
'avatar.jpg'
>>> normalize_jpeg('Avatar.JPEG')
'Avatar.jpg'
>>> normalize_jpeg('AVATAR.Jpg')
'AVATAR.jpg'

Normalize Whitespace¶

Make a function that replaces all instances of one or more whitespace characters with a single space.

Example usage:

>>> normalize_whitespace("hello  there")
"hello there"
>>> normalize_whitespace("""Hold fast to dreams
... For if dreams die
... Life is a broken-winged bird
... That cannot fly.
...
... Hold fast to dreams
... For when dreams go
... Life is a barren field
... Frozen with snow.""")
'Hold fast to dreams For if dreams die Life is a broken-winged bird That cannot fly. Hold fast to dreams For when dreams go Life is a barren field Frozen with snow.'

Compress blank lines¶

Write a function that accepts a string and an integer N and compresses runs of N or more consecutive empty lines into just N empty lines.

Example usage:

>>> compress_blank_lines("a\n\nb", max_blanks=1)
'a\n\nb'
>>> compress_blank_lines("a\n\nb", max_blanks=0)
'ab'
>>> compress_blank_lines("a\n\nb", max_blanks=2)
'a\n\nb'
>>> compress_blank_lines("a\n\n\n\nb\n\n\nc", max_blanks=2)
'a\n\n\nb\n\n\nc'

Normalize URL¶

I own the domain treyhunner.com. I prefer to link to my website as https://treyhunner.com, but I have some links that use http or use a www subdomain.

Write a function that normalizes all www.treyhunner.com and treyhunner.com links to use HTTPS and remove the www subdomain.

Example usage:

>>> normalize_domain("http://treyhunner.com/2015/12/python-list-comprehensions-now-in-color/")
'https://treyhunner.com/2015/12/python-list-comprehensions-now-in-color/'
>>> normalize_domain("https://treyhunner.com/2016/02/how-to-merge-dictionaries-in-python/")
'https://treyhunner.com/2016/02/how-to-merge-dictionaries-in-python/'
>>> normalize_domain("http://www.treyhunner.com/2015/11/counting-things-in-python/")
'https://treyhunner.com/2015/11/counting-things-in-python/'
>>> normalize_domain("http://www.treyhunner.com")
'https://treyhunner.com'
>>> normalize_domain("http://trey.in/give-a-talk")
'http://trey.in/give-a-talk'

Linebreaks¶

Write a function that accepts a string and converts linebreaks to HTML in the following way:

• text is surrounded by paragraphs
• text with two or more line breaks between is considered two separate paragraphs
• text with a single line break between is separated by a <br>

Example usage:

>>> convert_linebreaks("hello")
'<p>hello</p>'
>>> convert_linebreaks("hello\nthere")
'<p>hello<br>there</p>'
>>> convert_linebreaks("hello\n\nthere")
'<p>hello</p><p>there</p>'
>>> convert_linebreaks("hello\nthere\n\nworld")
'<p>hello<br>there</p><p>world</p>'

All Vowels¶

Find all words that are at most 9 letters long and contain every vowel (a, e, i, o, u) in any order.

Unique Letters¶

Find all words that have at least 10 letters and do not have any repeating letters.

HTML Encode Ampersands¶

Replace all & characters which are not part of HTML escape sequences by an HTML-encoded ampersand (&).

Example usage:

>>> encode_ampersands("This & that & that & this.")
'This & that & that & this.'
>>> encode_ampersands("A&W")
'A&W'

Pig Latin¶

Create a function that translates English phrases to pig latin.

Example usage:

>>> to_pig_latin("pig")
'igpay'
>>> to_pig_latin("trust")
'usttray'
>>> to_pig_latin("quack")
'ackquay'
>>> to_pig_latin("squeak")
'eaksquay'
>>> to_pig_latin("enqueue")
'enqueueay'
>>> to_pig_latin("sequoia")
'equoiasay'

Camel Case to Underscore¶

Make a function that converts camelCase strings to under_score strings.

Get Inline Markdown Links¶

Make a function that accepts a string and returns a list of all inline markdown links in the given string.

Inline markdown links look like this:

[text here](http://example.com)

Example usage:

>>> get_inline_links("""
... [Python](https://www.python.org)
... [Google](https://www.google.com)""")
[('Python', 'https://www.python.org'), ('Google', 'https://www.google.com')]

Broken Markdown Links¶

Make a function that accepts a string and returns a list of all reference-style markdown links that do not have a corresponding link definition.

Example usage:

>>> find_broken_links("""
... [working link][Python]
... [broken link][Google]
... [python]: https://www.python.org/""")
[('broken link', 'Google')]

As a bonus, make your function also work with implicit link names. For example:

>>> find_broken_links("""
... [Python][]
... [Google][]
... [python]: https://www.python.org/""")
[('Google', 'Google')]

Get All Markdown Links¶

Modify your get_inline_links function from the previous exercise to make a get_markdown_links function which finds all markdown links.

This function should work for inline links as well as reference links (including reference links with implicit link names).

Example usage:

>>> get_markdown_links("""
... [Python](https://www.python.org)
... [Google][]
... [Another link][example]
... [google]: https://www.google.com
... [example]: http://example.com""")
[('Python', 'https://www.python.org'), ('Google', 'https://www.google.com'), ('Another link', 'http://example.com')]