Gain insights into Python's regular expressions with practical examples, web scraping projects, coding exercises, and beginner-friendly lectures. Delve into real-world data and enhance your Python skills effectively.

Regex with Python? Many of you do not find this combination easy, which partly happens because of the Python's obfuscated regex documentation too! In this course, to make your life easy, I 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;
- 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
- Beginner friendly video lectures to explain the basic REGEX concepts.

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 course should get you going with Python Regex in less than 30mins. This course is a core component of the 'Learn Scientific Programming' project.

Python Regular Expressions with Data Scraping Projects

# The Search Function

The `search` function searches for first occurance of  a `re` pattern to string with optional flags.

Here is the syntax for this function −

````
re.search(pattern, string, flags=0)
````
Where, 
`pattern` is	the regular expression to be matched,
`string`	is the string to be searched to match the pattern at the beginning of string and
`flags`, which you can specify different flags using bitwise OR (`|`). 

# Match Flags

|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.|

# Return values

- The `re.search` function returns a match `object` on **success** and `None` upon failure. -
- Use `group(n)` or `groups()` function of match object to get matched expression, e.g., `group(n=0)`	 returns entire match (or specific subgroup `n`)
- The function `groups()` returns all matching subgroups in a tuple (empty if there weren't any).

# Example 1

Let's find the words before and after the word `to`:


# The Search Function

The `search` function searches for first occurance of  a `re` pattern to string with optional flags.

Here is the syntax for this function −

````
re.search(pattern, string, flags=0)
````
Where, 
`pattern` is	the regular expression to be matched,
`string`	is the string to be searched to match the pattern at the beginning of string and
`flags`, which you can specify different flags using bitwise OR (`|`). 

# Match Flags

|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.|

# Return values

- The `re.search` function returns a match `object` on **success** and `None` upon failure. -
- Use `group(n)` or `groups()` function of match object to get matched expression, e.g., `group(n=0)`	 returns entire match (or specific subgroup `n`)
- The function `groups()` returns all matching subgroups in a tuple (empty if there weren't any).

# Example 1

Let's find the words before and after the word `to`:


Python Regex search() function explained with examples.

Introduction

Python Regular Expressions Funtions

Python Regex - Look ahead and Look behind

Python Lazy and Greedy Search

Python Regex by Examples

References

Python regex `search` function

The Search Function

Match Flags