# String Functions
String functions are used to manipulate string data.
# CONCAT
concat(col1, col2, ...)
Concatenates arrays or strings. This function accepts any number of arguments and returns a string or an array.
# ENDSWITH
endswith(col1, col2)
Returns a boolean indicating whether the first string argument ends with the second string argument.
# FORMAT_TIME
format_time(col, format)
Format a datetime to string. The 'col' will be cast to datetime type if it is bigint, float or string type before formatting. Please check format patterns for how to compose the format.
# Format_time patterns
A pattern is used to create a format string. Patterns are based on a simple sequence of letters and symbols which is common in many languages like Java, etc. The supported symbols in Kuiper are
| Symbol | Meaning | Example |
|---|---|---|
| G | era | G(AD) |
| Y | year | YYYY(2004), YY(04) |
| M | month | M(1), MM(01), MMM(Jan), MMMM(January) |
| d | day of month | d(2), dd(02) |
| E | day of week | EEE(Mon), EEEE(Monday) |
| H | hour in 24 hours format | HH(15) |
| h | hour in 12 hours format | h(2), hh(03) |
| a | AM or PM | a(PM) |
| m | minute | m(4), mm(04) |
| s | second | s(5), ss(05) |
| S | fraction of second | S(.0), SS(.00), SSS(.000) |
| z | time zone name | z(MST) |
| Z | 4 digits time zone offset | Z(-0700) |
| X | time zone offset | X(-07), XX(-0700), XXX(-07:00) |
Examples:
- YYYY-MM-dd T HH:mm:ss -> 2006-01-02 T 15:04:05
- YYYY/MM/dd HH:mm:ssSSS XXX -> 2006/01/02 15:04:05.000 -07:00
# INDEXOF
indexof(col1, col2)
Returns the first index (0-based) of the second argument as a substring in the first argument.
# LENGTH
length(col)
Returns the number of characters in the provided string.
# LOWER
lower(col)
Returns the lowercase version of the given string.
# LPAD
lpad(col, 2)
Returns the string argument, padded on the left side with the number of spaces specified by the second argument.
# LTRIM
ltrim(col)
Removes all leading whitespace (tabs and spaces) from the provided string.
# NUMBYTES
numbytes(col)
Returns the number of bytes in the UTF-8 encoding of the provided string.
# REGEXP_MATCHES
regexp_matches(col, regex)
Returns true if the string (first argument) contains a match for the regular expression.
# REGEXP_REPLACE
regexp_replace(col, regex, replacement)
Replaces all substrings of the specified string value that matches regexp with replacement.
# REGEXP_SUBSTRING
regexp_substring(col, regex)
Returns the first substring of the specified string value that matches regexp.
# RPAD
rpad(col, 2)
Returns the string argument, padded on the right side with the number of spaces specified by the second argument.
# RTRIM
rtrim(col)
Removes all trailing whitespace (tabs and spaces) from the provided string.
# SUBSTRING
substring(col, start, length)
Returns the substring of the specified string value starting at the specified index position (0-based, inclusive) for up to the specified length of characters.
# STARTSWITH
startswith(col, str)
Returns a boolean indicating whether the first string argument starts with the second string argument.
# SPLIT_VALUE
split_value(col, str_splitter, index)
Split the value of the 1st parameter with the 2nd parameter, and return the value of split array that indexed with the 3rd parameter.
For example, split_value("/test/device001/message","/",0) AS a, the returned value of function is empty;
split_value("/test/device001/message","/",3) AS a, the returned value of function is message.
# TRIM
trim(col)
Removes all leading and trailing whitespace (tabs and spaces) from the provided string.
# UPPER
upper(col)
Returns the uppercase version of the given string.