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gregmalcolm committed Feb 6, 2011
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238 changes: 238 additions & 0 deletions python 2/koans/about_regex.py
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#!/usr/bin/env python
# -*- coding: utf-8 -*-

from runner.koan import *
import re
class AboutRegex(Koan):
"""
This koans are based on the Ben's book: Regular Expressions in 10 minutes.
I found this books very useful so I decided to write a koans in order to practice everything I had learned from it.
http://www.forta.com/books/0672325667/
"""

def test_matching_literal_text(self):
"""
Lesson 1 Matching Literal String
"""
string = "Hello, my name is Felix and this koans are based on the Ben's book: Regular Expressions in 10 minutes."
m = re.search(__, string)
self.assertTrue(m and m.group(0) and m.group(0)== 'Felix', "I want my name")

def test_matching_literal_text_how_many(self):
"""
Lesson 1 How many matches?
The default behaviour of most regular extression engines is to return just the first match.
In python you have the next options:
match() --> Determine if the RE matches at the beginning of the string.
search() --> Scan through a string, looking for any location where this RE matches.
findall() --> Find all substrings where the RE matches, and returns them as a list.
finditer() --> Find all substrings where the RE matches, and returns them as an iterator.
"""
string = "Hello, my name is Felix and this koans are based on the Ben's book: Regular Expressions in 10 minutes. Repeat My name is Felix"
m = re.match('Felix', string) #TIP: Maybe match it's not the best option
self.assertEqual(len(m),2, "I want to know how many times appears my name")

def test_matching_literal_text_not_case_sensitivity(self):
"""
Lesson 1 Matching Literal String non case sensitivity.
Most regex implementations also support matches that are not case sensitive. In python you can use re.IGNORECASE, in
Javascript you can specify the optional i flag.
In Ben's book you can see more languages.
"""
string = "Hello, my name is Felix or felix and this koans are based on the Ben's book: Regular Expressions in 10 minutes."
self.assertEqual(len(re.findall("felix", string,__)),2, "I want my name")

def test_matching_any_character(self):
"""
Lesson 1 Matching any character
. matches any character, alphabetic characters, digits and .
"""
string = "pecks.xlx\n" \
+ "orders1.xls\n" \
+ "apec1.xls\n" \
+ "na1.xls\n" \
+ "na2.xls\n" \
+ "sa1.xls"

#TIP: remember the issue of this lesson
self.assertEquals(len(re.findall(__, string)),3, "I want to find all files for North America(na) or South America(sa)")

def test_matching_special_character(self):
"""
Lesson 1 Matching special character
Uses \ if you want to match special character
"""
string = "sales.xlx\n" \
+ "sales1.xls\n" \
+ "orders1.xls\n" \
+ "apac1.xls\n" \
+ "sales2.xls\n" \
+ "na1.xls\n" \
+ "na2.xls\n" \
+ "sa1.xls"
#TIP you can use the pattern .a. which matches in above test but in this case matches more than you want
self.assertEquals(len(re.findall(__, string)),3, "I want to find all files for North America(na) or South America(sa)")

def test_matching_set_character(self):
"""
Lesson 2 Matching sets of characters
A set of characters is defined using the metacharacters [ and ]. Everything between them is part of the set and
any one of the set members must match (but not all).
"""
string = "sales.xlx\n" \
+ "sales1.xls\n" \
+ "orders3.xls\n" \
+ "apac1.xls\n" \
+ "sales2.xls\n" \
+ "na1.xls\n" \
+ "na2.xls\n" \
+ "sa1.xls\n" \
+ "ca1.xls"
#TIP you can use the pattern .a. which matches in above test but in this case matches more than you want
self.assertEquals(len(re.findall(__, string)),3, "I want to find all files for North America(na) or South America(sa), but not (ca)")

def test_using_character_set_ranges(self):
"""
Lesson 2 Using character set ranges
The previous pattern could be [ns]a.\.xls and if a in the list had a file name sam.xls would be matched because the . matches all
characters, not just digits. This can be solved with Character sets.
You can use this pattern [ns]a[0123456789]\.xls but to simplify you can use a special metacharacter: - (hyphen). i.e [0-9]
- is only a metacharacter when used between [].
"""
string = "sales.xlx\n" \
+ "sales1.xls\n" \
+ "orders3.xls\n" \
+ "apac1.xls\n" \
+ "sales2.xls\n" \
+ "na1.xls\n" \
+ "na2.xls\n" \
+ "sa1.xls\n" \
+ "sam.xls\n" \
+ "ca1.xls"
self.assertEquals(len(re.findall(__, string)),3, "I want to find all files for North America(na) or South America(sa), but not (ca)")

def test_using_multiple_ranges(self):
"""
Lesson 2 Using character set ranges
The following are valid ranges:
A-Z matches all uppercase characters from A to Z
a-z matches all uppercase characters from a to z
A-F matches all uppercase characters from A to F
A-z matches all uppercase characters from A to z. This pattern also includes characters such as [ and ^
Any two ASCII characters may be specified as the range start and end.
"""
string = '<BODY BGCOLOR="#336633" TEXT="#FFFFFF" MARGINWIDTH="0" MARGINHEIGHT="0" TOPMARGIN="0" LEFTMARGIN="0">'
self.assertEquals(len(re.findall(__, string)),2, "I want to find all the colors in RGB")


def test_anything_but_matching(self):
"""
Lesson 2 Using character set ranges
Occsionally, you'll want a list of characters that you don't want to match.
Character sets can be negated using the ^ metacharacter.
"""
string = "sales.xlx\n" \
+ "sales1.xls\n" \
+ "orders3.xls\n" \
+ "apac1.xls\n" \
+ "sales2.xls\n" \
+ "sales3.xls\n" \
+ "europe2.xls\n" \
+ "sam.xls\n" \
+ "na1.xls\n" \
+ "na2.xls\n" \
+ "sa1.xls\n" \
+ "ca1.xls"
m = re.search(__, string)
self.assertTrue(m and m.group(0) and m.group(0)== 'sam.xls', "I want to find the name sam")

def using_metacharacters_escaping(self):
"""
Lesson 3 Using metacharacters
Metacharacters are characters that have special meaning within regular expressions.
Metacharacters can be escaped by preceding them with a backslash, therefore \. matches .
"""
string = "var myArray = new Array();\n" \
+ "if (myArray[0]) { \n" \
+ "}"
m = re.search("myArray[0]", string) #TIP: This pattern matches "myArray0" because [ and ] are metacharacters
self.assertTrue(m and m.group(0) and m.group(0)== 'myArray[0]', "I want to find myArray[0]")

def using_metacharacters_matching_white_spaces(self):
"""
Lesson 3 Matching whitespace character
Sometimes you'll have to match nonprinting whitespace characters embedded in your text. For example tab characters
or line breaks .
In this cases you can use these special metacharacters:
[\b] Backspace
\f Form feed
\n Line feed
\r Carriage return
\t Tab
\v Vertical tab
"""
f = open('koans/regex_cvs', 'r')
string = f.read()
#This text contains a series of records in comma-delimited format (cvs). Before processing the records, you need
# to remove any blank lines in the data.
m = re.search("", string)
self.assertTrue(m and m.group(0) and m.group(0)== '\n\n', "I want to find the blank lines")

def using_metacharacters_matching_digits(self):
"""
Lesson 3 Using metacharacters
As you have seen in Lesson 2, [0-9] is a shorcut for [0123456789] and is used to match any digit.
To match anything other than a digit, the set can be negated as [^0-9].
With the next metacharacters you can do the same:
\d match any digit (same as [0-9])
\D match any nondigit (same as [0-9])
"""
string = "var myArray = new Array();\n" \
+ "if (myArray[0]) { \n" \
+ " alert('Learning regex'); \n" \
+ "} \n" \
+ "if (myArray[1]) { \n" \
+ " alert('With this great book');\n" \
+ "} \n"

self.assertEquals( len(re.findall(__, string)), 2, "I want to find all uses of myArray")


def using_metacharacters_matching_alphanumeric_characters(self):
"""
Lesson 3 Using metacharacters
Like with the digits you have special characters for alphanumeric characters:
\w Any alphanumeric character in uppercase or lowercase and underscore: [a-zA-Z0-9_]
\W Any nonalphanumeric or underscore character: [^a-zA-Z0-9_]
Here you have a list of IDs made of 3 characters/digits/underscores, 1 hyphen and 3 characters/digits/underscores:
A1A-B_A or BA_-2e3 or 1_2-34R
"""
string = "A_1-DRA\n" \
+"A01-2ER\n" \
+"A01-(4d\n" \
+"B11=223\n" \
+"A1A-B_A\n" \
+"1_2-34R\n" \
+"BA_-2e3"

self.assertEquals( len(re.findall(__, string)), 5, "I want to find the ids")
6 changes: 6 additions & 0 deletions python 2/koans/regex_cvs
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"101", "Ben", "Forta
"102", "Felix", "Lopez"

"103", "Roberta", "Robertson"
"104", "Bob", "Bobson"

28 changes: 28 additions & 0 deletions python 2/koans/regex_solutions.txt
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test_matching_literal_text:
Felix
test_matching_literal_text_how_many:
findall
test_matching_literal_text_not_case_sensitivity:
re.findall("felix", string, re.IGNORECASE)
test_matching_any_character:
.a OR .a.
test_matching_special_character:
.a.\.
test_matching_set_character:
[ns]a.\. Actually this pattern is not quite right either. If a file named usa1.xls existed, it would match.
The solution to this problem involves matching, which will be covered later, in "Position Matching.
test_using_character_set_ranges:
[ns]a[0-9]\.xls
test_using_multiple_ranges:
#[0-9A-Fa-f][0-9A-Fa-f][0-9A-Fa-f][0-9A-Fa-f][0-9A-Fa-f][0-9A-Fa-f] OR #[0-9A-Fa-f]{6} but the latter will be seen later
test_anything_but_matching:
[ns]a[^0-9]\.xls
using_metacharacters_escaping:
myArray\[0\]
using_metacharacters_macthing_white_spaces:
\n\n
IMPORTANT: Windows uses a carriage return line fedd combination used as an end-of-line marker, so you need to use \r\n.
using_metacharacters_matching_digits:
myArray\[\d\]
using_metacharacters_matching_alphanumeric_characters:
\w\w\w-\w\w\w

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