Python substring extraction is primarily done using string slicing, which uses the syntax string[start:end:step]. This allows you to extract a portion of a string based on start and end indices (with the end index being exclusive) and an optional step value.
Get substring from start index to end:
string[2:7]returns characters from index 2 up to (but not including) index 7.Get substring from start to end of string: Omit the end index:
string[2:]returns from index 2 to the end.Get substring from beginning to end index: Omit the start index:
string[:5]returns the first 5 characters.Get last n characters: Use negative indexing:
string[-3:]returns the last 3 characters.Get a single character: Use a single index:
string[0]returns the first character;string[-1]returns the last.
Key points:
Python uses 0-based indexing.
If the end index exceeds the string length, Python returns the available portion without raising an error.
Negative indices count from the end of the string.
Use
into check if a substring exists:'test' in 'testing'returnsTrue.Use
.find()to get the index of a substring (returns -1 if not found), or.index()which raises an exception if not found.
For more complex patterns, use the re module with re.search() and .group() to extract substrings based on regular expressions.
Copy>>> x = "Hello World!"
>>> x[2:]
'llo World!'
>>> x[:2]
'He'
>>> x[:-2]
'Hello Worl'
>>> x[-2:]
'd!'
>>> x[2:-2]
'llo Worl'
Python calls this concept "slicing" and it works on more than just strings. Take a look here for a comprehensive introduction.
Answer from Paolo Bergantino on Stack OverflowW3Schools
w3schools.com › python › python_strings.asp
Python Strings
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Top answer 1 of 16
3829
Copy>>> x = "Hello World!"
>>> x[2:]
'llo World!'
>>> x[:2]
'He'
>>> x[:-2]
'Hello Worl'
>>> x[-2:]
'd!'
>>> x[2:-2]
'llo Worl'
Python calls this concept "slicing" and it works on more than just strings. Take a look here for a comprehensive introduction.
2 of 16
505
Just for completeness as nobody else has mentioned it. The third parameter to an array slice is a step. So reversing a string is as simple as:
Copysome_string[::-1]
Or selecting alternate characters would be:
Copy"H-e-l-l-o- -W-o-r-l-d"[::2] # outputs "Hello World"
The ability to step forwards and backwards through the string maintains consistency with being able to array slice from the start or end.
How to extract a substring from a string in Python 3 - Stack Overflow
I am trying to pull a substring out of a function result, but I'm having trouble figuring out the best way to strip the necessary string out using Python. Output Example: [ More on stackoverflow.com
Python: best way to find and extract substring from a string?
Your post is kind of messed up because you didn't format your example properly as a code block. But based on the way your Markdown formatting came out, I'm guessing that the three strings you're looking for are on lines by themselves that start with a # symbol. In that case you could just do something along the lines of: lines = string.split('\n') heading_lines = [l for l in lines if l.startswith('#')] title, description, results = [l.strip('#').strip() for l in heading_lines[:3]] More on reddit.com
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October 9, 2024How to find all occurrences of a substring in a string while ignore some characters in Python?
You could use re for this. ex import re long_string = 'this is a t`es"t. Does the test work?' small_string = "test" chars_to_ignore = ['"', '`'] print(re.findall(f"[{''.join(chars_to_ignore)}]*".join(small_string), long_string)) More on reddit.com
6
1
July 25, 2024Medium Leetcode question - Longest Substring Without Repeating Characters
I'm a bit surprised that this does not exceed the time limit. You're restarting the loop once for each possible starting position, right? That makes the runtime quadratic. And yes, there is a better way. The problem with your original code was that it assumed that, if we find a duplicate, the next duplicate-free substring to consider must start here. But as you found out, that's not true: If we take "abacdef", the longest duplicate-free substring is "bacdef", not "acdef". So how do we find this without trying every starting position? By taking into account the last occurrence of the duplicated character. That is, after finding the duplicate 'a', we don't continue with an empty substring, we continue with a substring that starts after the previous 'a'. More on reddit.com
2
3
June 22, 2024Videos
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#26 Python Tutorial for Beginners | Python Substring | How to get ...
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Python Program #59 - Get a Substring of a String in Python - YouTube
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Identifying a Substring Within a Python String - YouTube
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String Slicing in Python for Beginners - How to get a Substring ...
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How do I get a substring of a string in Python? - YouTube
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string substring (Python) - YouTube
Csuk
coder.csuk.io › coder_course_page › string-methods-in-python-find-replace-split-strip-left-mid-right
String Methods in Python (find, replace, split, strip, left, mid, right) – CSUK:Coder
Understanding how to find, replace, split, and slice strings will give you the ability to handle almost any text-related problem in Python. Here’s a breakdown of the string methods we'll cover: .find() – This method is used to locate a substring within a string.
freeCodeCamp
freecodecamp.org › news › python-substring-how-to-slice-a-string
Python Substring – How to Slice a String
July 27, 2021 - We can define a substring as a sequence of characters within a string. From the previous example, Python substrings can be "Friday", "at", and "meet", for example.
Codecademy
codecademy.com › docs › python › substrings
Python | Substrings | Codecademy
June 18, 2025 - A substring in Python is a contiguous sequence of characters extracted from an original string.
IONOS
ionos.com › digital guide › websites › web development › python substring
How to create and edit Python substrings
July 19, 2023 - The syntax of slicing in Python looks like this: ... First, we created a string called “s”. In the second line of the code example, you can see how slicing works. After the name of the string, there are square brackets. Inside the brackets, you’ll find the start index 0 followed by a colon and then the end index 6. The “result” variable then stores a substring of “s”, which consists of the characters from the 0th index up to and including the 5th index.
Server Academy
serveracademy.com › blog › python-substring-tutorial
Python Substring Tutorial - Server Academy
May 28, 2024 - For your convenience we have embedded a Python 3 fiddler here on this post so you can practice what you learn in this blog post. A substring is simply a smaller string that exists within a larger string. Think of it like a piece of a bigger puzzle.
GeeksforGeeks
geeksforgeeks.org › python › how-to-substring-a-string-in-python
How to Substring a String in Python - GeeksforGeeks
July 23, 2025 - In this example, we are trying to extract the starting word from the string.we used string slicing to extract the substring "Geeks" from the beginning of the string.
LearnDataSci
learndatasci.com › solutions › python-substring
Quickly Substring a String in Python – LearnDataSci
Using this approach will return a substring with everything that comes before the end index. See below for an example of this using example_string (note that this produces the same result as example_string[0:7] in the intro): example_string = 'example_string' example_string[:7] ... Notice that the second 'e' is at index 6, so using an end point of 7, Python returns a substring containing everything that comes before.
Udemy
blog.udemy.com › home › substrings in python and the many ways you can use them
Substrings in Python and Ways You Can Use Them - Udemy Blog
March 31, 2022 - This article will introduce you ... If a string is a sequence of characters, a Python substring is simply a sequence of characters within another string....
Agnostic Development
agnosticdev.com › content › how-find-substring-string-python
How to Find a Substring in a String with Python | Agnostic Development
November 23, 2018 - The code samples in this tutorial will cover Python 2.7.13 and Python 3.6.1 and will be tested on Ubuntu (16.04) Linux and macOS Sierra 10.12.4. I have not tested the code in a Window's environment, but if you are using a Linux subsystem on Windows with Python available, the results should be fairly similar, but cannot be guaranteed. ... The most straightforward and widely available example of how to determine if a substring is available in a parent string is by performing a boolean check to determine if a parent string is containing a substring value.
Built In
builtin.com › software-engineering-perspectives › python-substring-indexof
5 Ways to Find the Index of a Substring in Python | Built In
Below is a summary of what you need to remember about each Python string method. str.find(), str,index(): These return the lowest index of the substring.
Python documentation
docs.python.org › 3 › library › stdtypes.html
Built-in Types — Python 3.14.3 documentation
1 week ago - The find() method should be used only if you need to know the position of sub. To check if sub is a substring or not, use the in operator:
Sentry
sentry.io › sentry answers › python › extract a substring from a string in python
Extract a substring from a string in Python | Sentry
April 15, 2023 - We can also use regular expressions to extract a substring using the re module in Python. You can use the re.search() function to search the string for a specific pattern. The method returns a match object if a match is found. You can then use the .group() method on the match object to extract the matching substring.
iO Flood
ioflood.com › blog › python-substring-quick-reference
Python Substring Quick Reference
January 31, 2024 - Remember, Python indexing starts at 0, so index 2 is the third character and slicing is exclusive of the end index. ... A substring is a portion of a string. It can be as short as a single character or as long as the entire string itself.
Top answer 1 of 4
1
Many many ways to solve this. Here are two examples:
First one is a simple replacement of your unwanted characters.
targetstring = '[<THIS STRING-STRING-STRING THAT THESE THOSE>]'
#ALTERNATIVE 1
newstring = targetstring.replace(r" THAT THESE THOSE>]", '').replace(r"[<THIS ", '')
print(newstring)
and this drops everything except your target pattern:
#ALTERNATIVE 2
match = "STRING-STRING-STRING"
start = targetstring.find(match)
stop = len(match)
targetstring[start:start+stop]
These can be shortened but thought it might be useful for OP to have them written out.
I found this extremely useful, might be of help to you as well: https://www.computerhope.com/issues/ch001721.htm
2 of 4
0
If by '"[<THIS " &" THAT THESE THOSE>]" are static' you mean that they are always the exact same string, then:
s = "[<THIS STRING-STRING-STRING THAT THESE THOSE>]"
before = len("[<THIS ")
after = len(" THAT THESE THOSE>]")
s[before:-after]
# 'STRING-STRING-STRING'
Python documentation
docs.python.org › 3 › tutorial › introduction.html
3. An Informal Introduction to Python — Python 3.14.3 documentation
In addition to indexing, slicing is also supported. While indexing is used to obtain individual characters, slicing allows you to obtain a substring:
DigitalOcean
digitalocean.com › community › tutorials › python-string-substring
Python String Substring | DigitalOcean
August 4, 2022 - A substring is the part of a string. Python string provides various methods to create a substring, check if it contains a substring, index of substring etc. …
Python
docs.python.org › 3 › library › string.html
string — Common string operations
Template strings provide simpler string substitutions as described in PEP 292. A primary use case for template strings is for internationalization (i18n) since in that context, the simpler syntax and functionality makes it easier to translate than other built-in string formatting facilities in Python.
Frontendor
frontendor.com › blog › how-python-substring-a-string
How Python Substring A String
February 15, 2021 - In python substring is a sequence of characters within another string, In python, often they call it slicing a string.