5.2 Itse1359-1850-regular expressions

Table of contents

• Preface
• Questions
  • 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15
• Figure index
• Answers
• Miscellaneous

Preface

This module is one in a collection of modules on Python designed for teaching ITSE 1359 Introduction to Scripting Languages: Python at Austin Community College in Austin, TX.

This module contains review questions and answers keyed to material on the following web sites:

• The Python Standard Library: 6.2. re -- Regular expression operations
• The Python Standard Library: 2. Built-in Functions
• Charming Python: Text processing in Python
• tutorialspoint -- Python Regular Expressions
• Regular Expression HOWTO
• Python Course -- Python 3 Tutorial -- Regular Expressions
• Python Course -- Python 3 Tutorial -- Advanced Regular Expressions
• Python Course -- Python 3 Tutorial -- Lambda, filter, reduce and map
• Python Notes (0.14.0) 9. The regular expression module
• Python Library Reference -- 4.2.5 Match Objects

Once you study that material, you should be able to answer the review questions in this module.

The questions and the answers in this module are connected by hyperlinks to make it easy for you to navigate from the question to the answer and back again.

(Note to blind and visually impaired students: with the exception of two bitmap images that are used solely as spacers to separate the question sectionfrom the answer section, all of the material in this module is presented in plain text format and should be accessible using an audio screen reader or abraille display. Note however that the required indentation may not be properly represented by an audio screen reader.)

Questions

Question 1

Given: RE or re is an abbreviation for Regular Expression . Also, the primary module used for regular expressions in Python is named re . When using an RE pattern for matching characters, most letters and characters will simply match themselves. However, some characters are special metacharacters , and don't match themselves. Instead, they signal that some out-of-the-ordinary thing should be matched, or they affect other portions of the RE by repeating them or changing their meaning. (See Regular Expression HOWTO )

True or False? The following characters are included in the set of metacharacters:

[ $ !

Go to answer 1

Question 2

True or False? The metacharacters [ and ] are used for specifying a character class, which is a set of characters that you wish to match.

Go to answer 2

Question 3

True or False? Within a character class, characters can be listed individually, or a range of characters can be indicated by giving two characters and separating them by a three dashes as in [abc]or [a---c].

Go to answer 3

Question 4

True or False? The pattern [abc$] will match any of the characters a, b, c, or $.

Go to answer 4

Question 5

True or False? The pattern [^abc$] will match any of the characters a, b, c, or $.

Go to answer 5

Question 6

True or False? The code in the top panel of Figure 2 produces the output shown in the bottom panel of Figure 2 . (Hint: See (External Link) for lambda)