# Exercise 5b - Set complements
# You're processing some DNA sequences and you notice that some of them
# have been corrupted - they contain letters other than A,T,C and G!
# Write a regex that will let you remove the corrupted sequences.
from test_regex import test_regex
not_dna_regex = r'[^ATCG]' # replace ellipsis with a regex that matches
# sequences that contain anything other than A, T, C & G
test_regex('Not DNA regex', not_dna_regex, ['ATCHGA', '#*@!'],
['AGGGGGCTAA', 'ACGAT'])
# Notice that your regex matches non-alphabetic characters as well!
# Exercise 7
import re
from test_regex import test_regex
# Write a regex that matches filenames ending in .doc and .odt
word_file_regex = r'\.(doc|odt)$'
test_regex('Word file regex', word_file_regex,
['math_girls.doc', 'mathgirls2.odt'],
['other.ddt', 'odt', 'mathgirlsodt'])
# Exercise 5b - Set complements
# You're processing some DNA sequences and you notice that some of them
# have been corrupted - they contain letters other than A,T,C and G!
# Write a regex that will let you remove the corrupted sequences.
from test_regex import test_regex
not_dna_regex = r'[^ATCG]' # replace ellipsis with a regex that matches
# sequences that contain anything other than A, T, C & G
test_regex('Not DNA regex', not_dna_regex,
['ATCHGA', '#*@!'], ['AGGGGGCTAA', 'ACGAT'])
# Notice that your regex matches non-alphabetic characters as well!
# Exercise 2 - Specifying custom sets of characters
# We saw some metacharacters in the previous slide: \w, \d, \s
# Define custom character ranges that are equivalent to these,
# WITHOUT using metacharacters (escape sequences like \n are fine)
# Exercise 2a
digit_regex = r'[...]' # match definition of \d
# Exercise 2b
wordlike_regex = r'[...]' # match definition of \w (at least, for English)
# Exercise 2c
spacelike_regex = r'[...]' # match definition of \s
# No need to edit below this point. Run this program to see if your answers were correct.
from test_regex import test_regex
test_regex('Digit regex', digit_regex, '0123456789', 'aZ \t\n$_')
test_regex('Wordlike regex', wordlike_regex, 'ampBLY_058', ' \t\n-$')
test_regex('Spacelike regex', spacelike_regex, ' \t\r\n', 'ahlB_-$9')
# Exercise 7
import re
from test_regex import test_regex
# Write a regex that matches filenames ending in .doc and .odt
word_file_regex = r'...'
test_regex('Word file regex', word_file_regex,
['math_girls.doc', 'mathgirls2.odt'],
['other.ddt', 'odt'])
import re
from test_regex import test_regex
# ---------------
# Exercise 6a
# ---------------
# Write a regex that matches the words bad, baad, baaad
# for any arbitrary number of a's
animal_farm_bleat_regex = r'\bba+d\b' # replace the ellipsis with your regex
test_regex('Animal farm bleat', animal_farm_bleat_regex,
['baaaaaaad', 'This is baaaaaaaaaaad!'], # should match these
['bd', 'bacd', 'baaaaa', 'sinbaaaad']) # shouldn't match these
# ---------------
# Exercise 6b
# ---------------
# Write a regex that matches the word baaad (3 a's) up to baaaaaaaaaad (10 a's).
animal_farm_short_bleat_regex = r'\bba{3,10}d\b'
test_regex('Animal farm short bleat', animal_farm_short_bleat_regex,
['baaaaaaad', 'This is baaaaaaaaaad!'], # should match these
['bd', 'bacd', 'baaaaa', 'sinbaaaad', 'baad', 'baaaaaaaaaaaad']) # not these
# ---------------
# Exercise 5c - Set complements
# You're looking at a list of purchases again.
# Acme company uses product codes with A,B,C followed by three digits.
# Axeme company uses product codes X,Y,Z followed by three digits.
from test_regex import test_regex
# Write a regex to extract lines with just Acme and Axeme's product codes,
# *using a set complement* rather than r'[ABCXYZ]...'
# Also, make sure that the product code occurs at the *end* of the line
acme_axeme_regex = r'[^D-W]\d\d\d' # replace the ellipsis with your regex
# No need to edit below this line
matches = ['This line contains Acme product code C180',
'This line contains Axeme product X007']
nonmatches = ['This line contains Hugo\'s product code J982',
'This line contains an incorrect Axeme product code Z48A',
'This line contains Acme code C180 but it\'s not at the end.']
test_regex('Acme/Axeme regex', acme_axeme_regex, matches, nonmatches)
# Notice that we did something a bit dangerous here -
# the regex also matches product codes like '0000'.
# So, be careful when using set complements!
import re
from test_regex import test_regex
# ---------------
# Exercise 6a
# ---------------
# Write a regex that matches the words bad, baad, baaad
# for any arbitrary number of a's
animal_farm_bleat_regex = r'...' # replace the ellipsis with your regex
test_regex('Animal farm bleat', animal_farm_bleat_regex,
['baaaaaaad', 'This is baaaaaaaaaaad!'], # should match these
['bd', 'bacd', 'baaaaa', 'sinbaaaad']) # shouldn't match these
# ---------------
# Exercise 6b
# ---------------
# Write a regex that matches the word baaad (3 a's) up to baaaaaaaaaad (10 a's).
animal_farm_short_bleat_regex = r'...'
test_regex('Animal farm short bleat', animal_farm_short_bleat_regex,
['baaaaaaad', 'This is baaaaaaaaaad!'], # should match these
['bd', 'bacd', 'baaaaa', 'sinbaaaad', 'baad', 'baaaaaaaaaaaad']) # not these
# ---------------
# Exercise 2 - Specifying custom sets of characters
# We saw some metacharacters in the previous slide: \w, \d, \s
# Define custom character ranges that are equivalent to these,
# WITHOUT using metacharacters (escape sequences like \n are fine)
# Exercise 2a
digit_regex = r'[0-9]' # match definition of \d
# Exercise 2b
wordlike_regex = r'[a-zA-Z0-9_]' # match definition of \w (at least, for English)
# Exercise 2c
spacelike_regex = r'[\n\t\r ]' # match definition of \s
# No need to edit below this point. Run this program to see if your answers were correct.
from test_regex import test_regex
test_regex('Digit regex', digit_regex, '0123456789', 'aZ \t\n$_')
test_regex('Wordlike regex', wordlike_regex, 'ampBLY_058', ' \t\n-$')
test_regex('Spacelike regex', spacelike_regex, ' \t\r\n', 'ahlB_-$9')
# Exercise 5a - Set complements
from test_regex import test_regex
# Let's rearrange the metacharacter_regex from Exercise 4d.
# Why doesn't it work as we wanted?
metacharacter_regex = r'[^$.]'
test_regex('Metacharacter regex', metacharacter_regex, '^$.', 'a1')
# Edit the metacharacter regex below to make it work,
# in some way OTHER than rearranging the characters again
edited_metacharacter_regex = r'[\^\$\.]'
test_regex('Edited Metacharacter regex', edited_metacharacter_regex, '^$.',
'a1')
# So, saying "within character sets [], metacharacters have their
# regular meaning except backslashes" is true EXCEPT that
# ^ means complement if it's the first character [^...].
# Elsewhere, it means the caret character.
# The purpose of this exercise is to illustrate that metacharacters
# retain their regular meaning within character sets []
import re
from test_regex import test_regex
# Instructions: read the regex, and run the code to verify that
# it does indeed match the literal characters $, ^ and .
metacharacter_regex = r'[$^.]'
# Test regex to make sure it matches '^','$','.' and not 'a' or '1'.
test_regex('Metacharacter regex', metacharacter_regex, '^$.', 'a1')
# Exercise 5a - Set complements
import re
from test_regex import test_regex
# Let's rearrange the metacharacter_regex from Exercise 4d.
# Why doesn't it work as we wanted?
metacharacter_regex = r'[^$.]'
test_regex('Metacharacter regex', metacharacter_regex, '^$.', 'a1')
# Edit the metacharacter regex below to make it work,
# in some way OTHER than rearranging the characters again
edited_metacharacter_regex = r'[^$.]'
test_regex('Edited Metacharacter regex', edited_metacharacter_regex, '^$.', 'a1')
# So, saying "within character sets [], metacharacters have their
# regular meaning except backslashes" is true EXCEPT that
# ^ means complement if it's the first character [^...].
# Elsewhere, it means the caret character.
# Exercise 5c - Set complements
# You're looking at a list of purchases again.
# Acme company uses product codes with A,B,C followed by three digits.
# Axeme company uses product codes X,Y,Z followed by three digits.
from test_regex import test_regex
# Write a regex to extract lines with just Acme and Axeme's product codes,
# *using a set complement* rather than r'[ABCXYZ]...'
# Also, make sure that the product code occurs at the *end* of the line
acme_axeme_regex = r'[^D-W]\d\d\d' # replace the ellipsis with your regex
# No need to edit below this line
matches = [
'This line contains Acme product code C180',
'This line contains Axeme product X007'
]
nonmatches = [
'This line contains Hugo\'s product code J982',
'This line contains an incorrect Axeme product code Z48A',
'This line contains Acme code C180 but it\'s not at the end.'
]
test_regex('Acme/Axeme regex', acme_axeme_regex, matches, nonmatches)
# Notice that we did something a bit dangerous here -
# the regex also matches product codes like '0000'.
# So, be careful when using set complements!
