...
- String literals match specified strings exactly. Written using single quotes ('...') or double quotes ("...").
Regular expressions enable pattern-based matching. Regular expressions are written using forward slashes (/.../). The The syntax is based on JavaScript regular RE2 and PCRE regular expressions.
Info NOTE: Regular expressions are considered a developer-level capability and can have significant consequences if they are improperly specified. Unless you are comfortable with regular expressions, you should use
instead.D s item patterns patterns
are custom selectors for patterns in your data and provide a simpler and more readable alternative to regular expressions. They are written using backticks (`...`).D s item patterns patterns
...
| Pattern | Description |
|---|---|
| % | match any character, exactly once |
| %? | match any character, zero or one times |
| %* | match any character, zero or more times |
| %+ | match any character, one or more times |
| %{3} | match any character, exactly three times |
| %{3,5} | match any character, 3, 4, or 5 times |
| # | digit character [0-9] |
| {any} | match any character, exactly once |
| {start} | match the start of the line |
| {end} | match the end of the line |
| {alpha} | alpha character [A-Za-z_] |
| {upper} | uppercase alpha character [A-Z_] |
| {lower} | lowercase alpha character [a-z_] |
| {digit} | digit character [0-9] |
| {delim} | single delimiter character e.g :, ,, |, /, -, ., \s |
| {delim-ws} | single delimiter and all the whitespace around it |
| {alpha-numeric} | match a single alphanumeric character |
| {alphanum-underscore} | match a single alphanumeric character or underscore character |
| {at-username} | match @username values |
| {hashtag} | match #hashtag values |
| {zip}, {hex}, {phone}, {email} | extensible types, as regexes |
| {state}, {state-abbrev} | extensible types continued |
| {month}, {month-abbrev}, {url} | extensible types continued |
| {ip-address}, {hex-ip-address} | extensible types continued |
| {time}, {bool} | extensible types continued |
| {[...]} | character class matches characters in brackets |
| {![...]} | negated class matches characters not in brackets |
| (...) | grouping, including captures |
| #, %, ?, *, +, {, }, (, ), \, ’, \n, \t | escaped characters or pattern modifiers Use a double backslash (\\) to denote an escaped string literal. For more information, see Escaping Strings in Transforms. |
| | | logical OR |
- Logical AND is the implied operator when you concatenate text matching patterns.
- Logical NOT is managed using negated classes.
...
