Scientific Programmer - Python Regular Expressions: A Little Guide
Here you can read online Scientific Programmer - Python Regular Expressions: A Little Guide full text of the book (entire story) in english for free. Download pdf and epub, get meaning, cover and reviews about this ebook. year: 2018, publisher: leanpub.com, genre: Home and family. Description of the work, (preface) as well as reviews are available. Best literature library LitArk.com created for fans of good reading and offers a wide selection of genres:
Romance novel
Science fiction
Adventure
Detective
Science
History
Home and family
Prose
Art
Politics
Computer
Non-fiction
Religion
Business
Children
Humor
Choose a favorite category and find really read worthwhile books. Enjoy immersion in the world of imagination, feel the emotions of the characters or learn something new for yourself, make an fascinating discovery.
- Book:Python Regular Expressions: A Little Guide
- Author:
- Publisher:leanpub.com
- Genre:
- Year:2018
- Rating:3 / 5
- Favourites:Add to favourites
- Your mark:
Python Regular Expressions: A Little Guide: summary, description and annotation
We offer to read an annotation, description, summary or preface (depends on what the author of the book "Python Regular Expressions: A Little Guide" wrote himself). If you haven't found the necessary information about the book — write in the comments, we will try to find it.
Python + Regex?
Many of you do not find this combination easy, which partly happens because of the Pythons obfuscated regex documentation too! In this course, to make your life easy, we have used some real-world examples. The goals are: - Teach you how to use the Python regular expressions (re) module and relevant functions by running interactive examples.
Projects included:
- Project 2: Parsing data from a HTML file with Python and REGEX
- Project 3: PDF scraping in Python + REGEX
- Project 4: Web scraping in Python + REGEX
- Project 5: Amazon web crawling in Python + REGEX
This is a short course, should be pretty quick and easy to complete. However, it assumes that you have basic Python skills (see the other Python courses on this platform).
This book serves three simple goals:
- Teach you how to use the Python regular expressions (re) module and relevant functions by running examples;
- Educate you to deal with projects with real world data examples (e.g., pdf and web scraping, more coming soon!);
- Challenge you with coding exercises and quizzes; and
This book should be pretty quick and easy to complete. However, it assumes that you have basic Python skills (see the other Python books on this platform).
Scientific Programmer: author's other books
Who wrote Python Regular Expressions: A Little Guide? Find out the surname, the name of the author of the book and a list of all author's works by series.
Python Regular Expressions: A Little Guide — read online for free the complete book (whole text) full work
Below is the text of the book, divided by pages. System saving the place of the last page read, allows you to conveniently read the book "Python Regular Expressions: A Little Guide" online for free, without having to search again every time where you left off. Put a bookmark, and you can go to the page where you finished reading at any time.
Font size:
Interval:
Bookmark:
This book is for sale at http://leanpub.com/pythonregex
This version was published on 2018-09-09
* * * * *
This is a Leanpub book. Leanpub empowers authors and publishers with the Lean Publishing process. Lean Publishing is the act of publishing an in-progress ebook using lightweight tools and many iterations to get reader feedback, pivot until you have the right book and build traction once you do.
* * * * *
Hello coders! Lets start our quest with regular expressions (RegEx). In Python, the module re provides full support for Perl-like regular expressions in Python. We need to remember that there are many characters in Python, which would have special meaning when they are used in regular expression. To avoid bugs while dealing with regular expressions, we use raw strings as r'expression'.
The re module in Python provides multiple methods to perform queries on an input string. Here are the most commonly used methods:
re.match()re.search()re.split()re.sub()re.findall()re.compile()
We will look at these function and related flags with examples in the next section.
The following table lists the regular expression syntax that is available in Python. Note that any Regex can be concatenated to form new regular expressions; if X and Y are both regular expressions, then XY is also a regular expression.
| Pattern | Description |
|---|---|
. | Matches any single character except newline. Using m option allows it to match newline as well. |
^ | Matches the start of the string, and in re.MULTILINE (see the next lesson on how to change to multiline) mode also matches immediately after each newline. |
$ | Matches end of line. In re.MULTILINE mode also matches before a newline. |
[.] | Matches any single character in brackets. |
[^.] | Matches any single character not in brackets. |
* | Matches 0 or more occurrences of preceding expression. |
+ | Matches 1 or more occurrence of preceding expression. |
? | Matches 0 or 1 occurrence of preceding expression. |
{n} | Matches exactly n number of occurrences of preceding expression. |
{n,} | Matches n or more occurrences of preceding expression. |
{n, m} | Matches at least n and at most m occurrences of preceding expression. For example, x{3,5} will match from 3 to 5'x' characters. |
| Pattern | Description |
|---|---|
x | y | Matches either x or y. |
\d | Matches digits. Equivalent to [0-9]. |
\D | Matches nondigits. |
\w | Matches word characters. |
\W | Matches nonword characters. |
\z | Matches end of string. |
\G | Matches point where last match finished. |
\b | Matches the empty string, but only at the beginning or end of a word. Boundary between word and non-word and /B is opposite of /b. Example r"\btwo\b" for searching two from 'one two three'. |
\B | Matches nonword boundaries. |
\n, \t | Matches newlines, carriage returns, tabs, etc. |
\s | Matches whitespace. |
\S | Matches nonwhitespace. |
\A | Matches beginning of string. |
\Z | Matches end of string. If a newline exists, it matches just before newline. |
More details later:
| Pattern | Description |
|---|---|
(re) | Groups regular expressions and remembers matched text. |
(?: re) | Groups regular expressions without remembering matched text. For example, the expression (?:x{6})* matches any multiple of six x characters. |
(?#...) | Comment. |
(?= ...) | Matches if ... matches next, but doesnt consume any of the string. This is called a lookahead assertion. For example, Scientific (?=Python) will match Scientific only if its followed by Python. |
(?!...) | Matches if ... doesnt match next. This is a negative lookahead assertion. |
(?<=...) | Matches if the current position in the string is preceded by a match for ... that ends at the current position. |
match functionThe match function attempts to match a re pattern to string with optional flags.
Here is the syntax for this function
1 re.match(pattern, string, flags=0)Where,
patternisthe regular expression to be matched,stringis the string to be searched to match the pattern at the beginning of string andflags, which you can specify different flags using bitwise OR (|).
| Modifier | Description |
|---|---|
re.I | Performs case-insensitive matching. |
re.L | Interprets words according to the current locale. This interpretation affects the alphabetic group (\w and \W), as well as word boundary behavior (\b and \B). |
re.M | Makes $ match the end of a line and makes ^ match the start of any line. |
re.S | Makes a period (dot) match any character, including a newline. |
re.U | Interprets letters according to the Unicode character set. This flag affects the behavior of \w, \W, \b, \B. |
re.X | It ignores whitespace (except inside a set [] or when escaped by a backslash and treats unescaped # as a comment marker. |
Font size:
Interval:
Bookmark:
Similar books «Python Regular Expressions: A Little Guide»
Look at similar books to Python Regular Expressions: A Little Guide. We have selected literature similar in name and meaning in the hope of providing readers with more options to find new, interesting, not yet read works.
Discussion, reviews of the book Python Regular Expressions: A Little Guide and just readers' own opinions. Leave your comments, write what you think about the work, its meaning or the main characters. Specify what exactly you liked and what you didn't like, and why you think so.