Check if string only contains one character. So let’s crack on.
Check if string only contains one character. To prevent double negation (because I find them harder te read) I decided to use the following regex:. In Java, a simple and straightforward implementation would be either. Jan 14, 2013 · If you need to check if all the characters in the string are same and is equal to a given character, you need to remove all duplicates and check if the final result equals the single character. May 5, 2014 · Check if string contains only letters in javascript Asked 11 years, 3 months ago Modified 2 years, 5 months ago Viewed 172k times In Python, how to check if a string only contains certain characters? I need to check a string containing only a. Learn how to use regex to check if a string has at least one character. (period) and no other character. toString(); final int i = s. Jul 15, 2025 · If the function loops through the entire string without finding any alphabets or numbers, it means that the string only contains special characters. Jul 15, 2025 · In this article, we are going to see how to check whether the given string contains only a certain set of characters in Python. These defined characters will be represented using sets. final String substring0 = substring. Jul 10, 2015 · You're searching for * in the entire string by using 'Contains',so this will turn out to be true when the string contains * even once (atleast) along with other characters. Apr 20, 2012 · I wanted to check if a string only contains certain characters. isalnum () is a built-in Python function that checks whether all characters in a string are alphanumeric. In other words, isalnum () checks whether a string contains only letters or numbers or both. Options There are Jul 23, 2025 · Here are several methods to check if a string contains only alphabetic characters in JavaScript Using Regular Expression (/^ [A-Za-z]+$/) - Most USed The most common approach is to use a regular expression to match only alphabetic characters (both uppercase and lowercase). Check If A String Contains Certain Characters View on GitHub Check if a string contains certain characters As with all in bash, there is no good or bad solution when it comes to checking if a string contains certain characters or substrings. . Anyways, why is this question being downvoted? I'm curious. 9, and . In this case, the function prints "Yes". So let’s crack on. It mostly depends on the rest of the script or the collection, the coding style and your personal preference. z, 0. But if you are want to check if the string is just * (only), you should be using the solution posted by jodrell. Nov 24, 2024 · Discover effective techniques to verify if a string comprises only permitted characters in Python, including regex and C extensions. Step-by-step explanation and code examples included. Apr 21, 2017 · I want to check if a string contains only a single occurrence of the given substring (so the result of containsOnce("foo-and-boo", "oo") should be false). indexOf(substring0); Nov 16, 2010 · Without the ^ and $ anchors, the regex will match any string that contains at least one valid character, because a regex can match any substring of the string use pass it. fakktkzuobvoixfwcvjjlwicyvvoftannkztrdlyacuzhvbymzenqf