Start of string anchor ^
Q
What is the "start of string" anchor in a regular expression? How to use it?
How to write a regular expression using "start of string" anchor to validate discover credit card numbers like: 6011963280099774?
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A
The "start of string" anchor is an atomic zero-width assertion specifing that the match must occur at the beginning of the string. The "start of string" anchor is represented as '^'. For example:
^5\d* # matches MasterCard numbers starting with '5'
The regular expression to validate Discover credit card numbers:
^6011\d{12}
^ - matches 'start of string'
\d{12} - repeats \d 12 times
2013-01-26, 0👍, 0💬