Using Patterns to Match Broad Content Types
Problem
You want to classify values into broad categories.
Solution
Use a pattern that is similarly broad.
Discussion
If you need to know whether values are empty or nonempty, or consist only of certain types of characters, the patterns listed in the following table may suffice:
| Pattern | Type of value the pattern matches |
|---|---|
/^$/
| Empty value |
/./
| Nonempty value |
/^\s*$/
| Whitespace, possibly empty |
/^\s+$/
| Nonempty whitespace |
/\S/
| Nonempty, and not just whitespace |
/^\d+$/
| Digits only, nonempty |
/^[a-z]+$/i
| Alphabetic characters only (case-insensitive), nonempty |
/^\w+$/
| Alphanumeric or underscore characters only, nonempty |
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