Interlude - Regex

This is not a formal chapter, because the content in this chapter does not have a very strong relationship with the chapters before or after it, and it is not continuous. So, when divided by difficulty, this one is placed as the third Note.

In this one, we will explain a language that is very important in Python (at least in my personal opinion): Regular Expressions.

The first relatively important use of regular expressions is finding a single element that meets a requirement. Yes, it is that simple.

Here is a simple Cheat Sheet; otherwise, the later content would sound like a book from heaven.

This is taken from Google Gemini, shout out to Google AI.

How exactly do we search? Here is a simple example. You do not need to completely understand the principle; being able to use it is enough, so I will not say too much here.

import re

text = " I am an 18-year-olguy. "
match = re.search(r'\d+')

if(match):
    print(match.group())

# So here the value assigned to Match is "18"

I will not go into why match.group() prints 18 here. Everyone can look at the table above and test themselves.

The second function: find all elements that meet the requirement.

Here is the code implementation:

import re

text = "123-453-2144 and 134-435-2323"

match = re.findall(r'\d{3}-\d{4}-\d{3}', text)

# Here match is equal to these two randomly generated phone numbers (any resemblance is purely unintentional)

The third function: replacement

Here is the implementation:

import re

text = "TheGoat: Micheal Jordan"

result = re.sub(r'TheGoat: ', '', text)
# Here result is Micheal Jordan

I personally think this function is very useful. When you are processing a lot of data and see a Title before a name, the person will become very Distinctive, which is annoying. Removing the title in front at that moment feels great.

Finally, but not limited to these functions: splitting a String

Here is the code:

import re

text = "We, Should; Seperate. the String From: Here"

result = re.split(r'[\s:;.,]', text)
# This splits a character according to the position of the index

The relatively important functions and uses of Regex are now covered. Obviously, there are still many functions I did not mention, but because of the length, I will not list them one by one. Today (8.4) produced two pieces of content, which is really quite productive. See you next time～88～

这一章并非是一个正式章节，因为这一章要讲的内容和前后并没有太大的关系，也不连贯，所以按难度来划分，这一张排在了第三个Note的位置。

这一张，我们将讲解在Python里非常重要（至少个人认为）的一个语言：Regular Expressions。

regular expressions的第一个比较重要的作用就是找单一符合要求的元素，没错，就是这么简单。

这里给出一个简单的Cheat Sheet，不然的话后面的内容就会变得听天书了。

这里摘自Google Gemini，shout out to google AI

具体怎么样搜寻呢？这里给出一个简单的例子，不需要完全理解原理，会用就可以了，因此这里不过多赘述。

import re

text = " I am an 18-year-olguy. "
match = re.search(r'\d+')

if(match):
    print(match.group())

#那么这里Match被赋的值是“18”

这里为什么match.group()打印出来是18，就不赘述了，大家可以看上表，考验一下大家。

第二个功能：找到全部符合要求的元素。

这里附上代码实现：

import re

text = "123-453-2144 and 134-435-2323"

match = re.findall(r'\d{3}-\d{4}-\d{3}', text)

#这里的match就等于这两串随机生成的电话号码（如有雷同，纯属无意冒犯）

第三个功能：替换

这里附上实现：

import re

text = "TheGoat: Micheal Jordan"

result = re.sub(r'TheGoat: ', '', text)
#这里result就是Micheal Jordan

我个人认为这个功能十分有用，当你在处理很多数据时，看到名字前的Title，这个个人就会不会非常得Distinctive，很烦。这时去掉前面的title，很爽。

最后，但不仅限于这些功能：分割一个String

附上代码：

import re

text = "We, Should; Seperate. the String From: Here"

result = re.split(r'[\s:;.,]', text)
#这样根据index的位置，分割一个字符

Regex的比较重要的功能及用法已经讲完了，显然，仍有大量的功能我没有提及，限于篇幅，就不一一列举了，今天（8.4）产出了两篇内容，真的算高产了，那我们下期见～88～

Interlude - RegexInterlude - Regex

Interlude - Regex