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Regex for first character

Regex for first character

A character is a unit of information that represents one or more letters i.e., from a-z or A-Z. In this article let's understand how we can create a regex for first character and how regex can be matched for a given first character.

Regex (short for regular expression) is a powerful tool used for searching and manipulating text. It is composed of a sequence of first characters that define a search pattern. Regex can be used to find patterns in large amounts of text, validate user input, and manipulate strings. It is widely used in programming languages, text editors, and command line tools.

Structure of the string

The word should have the following criteria and structure-

  • one or more characters
  • the first character should be a valid character

Regex for checking if first character is valid or not

Regular Expression for first character-


Test string examples for the above regex-

Input StringMatch Output
Hello WorldH
The world is a nice placeT

Here is a detailed explanation of the above regex-


^ asserts position at start of a line
1st Capturing Group ([\S\-])
Match a single character present in the list below [\S\-]
\S matches any non-whitespace character (equivalent to [^\r\n\t\f\v ])
\- matches the character - with index 4510 (2D16 or 558) literally (case sensitive)
Global pattern flags
g modifier: global. All matches (don't return after first match)
m modifier: multi line. Causes ^ and $ to match the begin/end of each line (not only begin/end of string)

Hope this article was useful to check and match the first character in a sentence.