We hear more and more about natural language processing. In today’s world, the amount of text content produced is growing exponentially. In order to process a text with a machine learning model, it is important to find certain information and numerical features about the text. What Are N-Grams? N-Grams are one of the tools to …
Problem Formulation In Python’s interactive mode, each line is assumed to be an expression that is evaluated. The return value is provided to the user. Thus, if you evaluate a string expression or call a function or an operation that returns a string, the output will display quotes around the string to tell the user …
What regular expressions can be used to match Bitcoin addresses? A regular expression for validating Bitcoin addresses must check that the string is 26-35 characters long, start with “1” or “3” or “bc1” consists of uppercase or lowercase alphabetic and numeric characters, and ensure it doesn’t contain ambiguous characters. Not allowed are the uppercase letter …
Problem Formulation Given a string s. How to find the substring s’ between an opening and a closing parentheses? Consider the following examples: Input: ‘Learn Python (not C++)’ Output: ‘not C++’ Input: ‘function(a, b, c, d)’ Output: ‘a, b, c, d’ Input: ‘(a+(b+c))’ Output: ‘a+(b+c)’ Method 1: Slicing and str.find() The simplest way to extract …
Python Regex to Return String Between Parentheses Read More »
đĄÂ Summary: This blog explores the steps to remove all non-alphabet characters from a given string. The ‘re’ module in Python provides regular expression operations, to process text. One uses these operations to manipulate text in strings. The compile() method in conjunction with the sub() method can remove all non-alphabet characters from a given string. Note: …
How To Remove All Non-Alphabet Characters From A String? Read More »
In this article, I present 7 Python scripts that can be used to determine if a string contains nothing but digits 0 – 9. All 7 scripts work for uncomplicated strings â those that donât have unusual or non-English characters, and do not contain spaces. To understand the idiosyncrasies of each script, see the caution …
How to Check if a Python String Contains Only Digits? Read More »
A Quick Introduction To Python’s ‘re’ Module âHow to extract digits or numbers from a stringâ is a common search by Python users in Google, and a frequent query in forums such as Stack Overflow. The answers invariably talk to two main solutions and in this article, I intend to focus down on one of …
The backslash escape character ‘\’ is a special Python string character that is usually followed by an alphabetic character. For example, the tabular whitespace ‘\t’ and newline ‘\n’. In regular expressions, you can use the single escape to remove the special meaning of regex symbols. For example, to match the dot or asterisk characters ‘.’ …
How to Escape Special Characters of a Python String with a Single Backslash? Read More »
Problem Formulation Say, you use the re.split(pattern, string) function to split a string on all occurrences of a given pattern. If the pattern appears at the beginning or the end of the string, the resulting split list will contain empty strings. How to get rid of the empty strings automatically? Here’s an example: Note the …
While refactoring my Python code, I thought of the following question. Can You Use a Regular Expression with the Python endswith() Method? The simple answer is no because if you can use a regex, you won’t even need endswith()! Instead, use the re.match(regex, string) function from the re module. For example, re.match(“^.*(coffee|cafe)$”, tweet) checks whether …
Python endswith() Tutorial – Can We Use Regular Expressions? Read More »
Problem Formulation: How to check if all characters of a string are uppercase? Background: A string is a sequence of characters, and is amongst the most commonly used and popular data types in Python. Strings can be enclosed by either single or double quotes and are âimmutableâ, meaning they canât be changed once created. There …
Check if All Characters of a String are Uppercase Read More »
Iâm sitting in front of my computer refactoring Python code and have just thought of the following question: Can You Use a Regular Expression with the Python string.startswith() Method? The short answer is no. The string.startswith() method doesn’t allow regular expression inputs. And you don’t need it because regular expressions can already check if a …
You Cannot Use Python Regex in startswith(). Do This Instead. Read More »