mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-16 20:53:27 +00:00
339 lines
9.6 KiB
Markdown
339 lines
9.6 KiB
Markdown
---
|
|
toc_priority: 47
|
|
toc_title: Splitting and Merging Strings and Arrays
|
|
---
|
|
|
|
# Functions for Splitting and Merging Strings and Arrays {#functions-for-splitting-and-merging-strings-and-arrays}
|
|
|
|
## splitByChar(separator, s) {#splitbycharseparator-s}
|
|
|
|
Splits a string into substrings separated by a specified character. It uses a constant string `separator` which consisting of exactly one character.
|
|
Returns an array of selected substrings. Empty substrings may be selected if the separator occurs at the beginning or end of the string, or if there are multiple consecutive separators.
|
|
|
|
**Syntax**
|
|
|
|
``` sql
|
|
splitByChar(separator, s)
|
|
```
|
|
|
|
**Arguments**
|
|
|
|
- `separator` — The separator which should contain exactly one character. [String](../../sql-reference/data-types/string.md).
|
|
- `s` — The string to split. [String](../../sql-reference/data-types/string.md).
|
|
|
|
**Returned value(s)**
|
|
|
|
Returns an array of selected substrings. Empty substrings may be selected when:
|
|
|
|
- A separator occurs at the beginning or end of the string;
|
|
- There are multiple consecutive separators;
|
|
- The original string `s` is empty.
|
|
|
|
Type: [Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md)).
|
|
|
|
**Example**
|
|
|
|
``` sql
|
|
SELECT splitByChar(',', '1,2,3,abcde');
|
|
```
|
|
|
|
``` text
|
|
┌─splitByChar(',', '1,2,3,abcde')─┐
|
|
│ ['1','2','3','abcde'] │
|
|
└─────────────────────────────────┘
|
|
```
|
|
|
|
## splitByString(separator, s) {#splitbystringseparator-s}
|
|
|
|
Splits a string into substrings separated by a string. It uses a constant string `separator` of multiple characters as the separator. If the string `separator` is empty, it will split the string `s` into an array of single characters.
|
|
|
|
**Syntax**
|
|
|
|
``` sql
|
|
splitByString(separator, s)
|
|
```
|
|
|
|
**Arguments**
|
|
|
|
- `separator` — The separator. [String](../../sql-reference/data-types/string.md).
|
|
- `s` — The string to split. [String](../../sql-reference/data-types/string.md).
|
|
|
|
**Returned value(s)**
|
|
|
|
Returns an array of selected substrings. Empty substrings may be selected when:
|
|
|
|
Type: [Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md)).
|
|
|
|
- A non-empty separator occurs at the beginning or end of the string;
|
|
- There are multiple consecutive non-empty separators;
|
|
- The original string `s` is empty while the separator is not empty.
|
|
|
|
**Example**
|
|
|
|
``` sql
|
|
SELECT splitByString(', ', '1, 2 3, 4,5, abcde');
|
|
```
|
|
|
|
``` text
|
|
┌─splitByString(', ', '1, 2 3, 4,5, abcde')─┐
|
|
│ ['1','2 3','4,5','abcde'] │
|
|
└───────────────────────────────────────────┘
|
|
```
|
|
|
|
``` sql
|
|
SELECT splitByString('', 'abcde');
|
|
```
|
|
|
|
``` text
|
|
┌─splitByString('', 'abcde')─┐
|
|
│ ['a','b','c','d','e'] │
|
|
└────────────────────────────┘
|
|
```
|
|
|
|
## splitByRegexp(regexp, s) {#splitbyregexpseparator-s}
|
|
|
|
Splits a string into substrings separated by a regular expression. It uses a regular expression string `regexp` as the separator. If the `regexp` is empty, it will split the string `s` into an array of single characters. If no match is found for this regular expression, the string `s` won't be split.
|
|
|
|
**Syntax**
|
|
|
|
``` sql
|
|
splitByRegexp(regexp, s)
|
|
```
|
|
|
|
**Arguments**
|
|
|
|
- `regexp` — Regular expression. Constant. [String](../data-types/string.md) or [FixedString](../data-types/fixedstring.md).
|
|
- `s` — The string to split. [String](../../sql-reference/data-types/string.md).
|
|
|
|
**Returned value(s)**
|
|
|
|
Returns an array of selected substrings. Empty substrings may be selected when:
|
|
|
|
- A non-empty regular expression match occurs at the beginning or end of the string;
|
|
- There are multiple consecutive non-empty regular expression matches;
|
|
- The original string `s` is empty while the regular expression is not empty.
|
|
|
|
Type: [Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md)).
|
|
|
|
**Example**
|
|
|
|
Query:
|
|
|
|
``` sql
|
|
SELECT splitByRegexp('\\d+', 'a12bc23de345f');
|
|
```
|
|
|
|
Result:
|
|
|
|
``` text
|
|
┌─splitByRegexp('\\d+', 'a12bc23de345f')─┐
|
|
│ ['a','bc','de','f'] │
|
|
└────────────────────────────────────────┘
|
|
```
|
|
|
|
Query:
|
|
|
|
``` sql
|
|
SELECT splitByRegexp('', 'abcde');
|
|
```
|
|
|
|
Result:
|
|
|
|
``` text
|
|
┌─splitByRegexp('', 'abcde')─┐
|
|
│ ['a','b','c','d','e'] │
|
|
└────────────────────────────┘
|
|
```
|
|
|
|
## splitByWhitespace(s) {#splitbywhitespaceseparator-s}
|
|
|
|
Splits a string into substrings separated by whitespace characters.
|
|
Returns an array of selected substrings.
|
|
|
|
**Syntax**
|
|
|
|
``` sql
|
|
splitByWhitespace(s)
|
|
```
|
|
|
|
**Arguments**
|
|
|
|
- `s` — The string to split. [String](../../sql-reference/data-types/string.md).
|
|
|
|
**Returned value(s)**
|
|
|
|
Returns an array of selected substrings.
|
|
|
|
Type: [Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md)).
|
|
|
|
**Example**
|
|
|
|
``` sql
|
|
SELECT splitByWhitespace(' 1! a, b. ');
|
|
```
|
|
|
|
``` text
|
|
┌─splitByWhitespace(' 1! a, b. ')─┐
|
|
│ ['1!','a,','b.'] │
|
|
└─────────────────────────────────────┘
|
|
```
|
|
|
|
## splitByNonAlpha(s) {#splitbynonalphaseparator-s}
|
|
|
|
Splits a string into substrings separated by whitespace and punctuation characters.
|
|
Returns an array of selected substrings.
|
|
|
|
**Syntax**
|
|
|
|
``` sql
|
|
splitByNonAlpha(s)
|
|
```
|
|
|
|
**Arguments**
|
|
|
|
- `s` — The string to split. [String](../../sql-reference/data-types/string.md).
|
|
|
|
**Returned value(s)**
|
|
|
|
Returns an array of selected substrings.
|
|
|
|
Type: [Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md)).
|
|
|
|
**Example**
|
|
|
|
``` sql
|
|
SELECT splitByNonAlpha(' 1! a, b. ');
|
|
```
|
|
|
|
``` text
|
|
┌─splitByNonAlpha(' 1! a, b. ')─┐
|
|
│ ['1','a','b'] │
|
|
└───────────────────────────────────┘
|
|
```
|
|
|
|
## arrayStringConcat(arr\[, separator\]) {#arraystringconcatarr-separator}
|
|
|
|
Concatenates string representations of values listed in the array with the separator. `separator` is an optional parameter: a constant string, set to an empty string by default.
|
|
Returns the string.
|
|
|
|
## alphaTokens(s) {#alphatokenss}
|
|
|
|
Selects substrings of consecutive bytes from the ranges a-z and A-Z.Returns an array of substrings.
|
|
|
|
**Example**
|
|
|
|
``` sql
|
|
SELECT alphaTokens('abca1abc');
|
|
```
|
|
|
|
``` text
|
|
┌─alphaTokens('abca1abc')─┐
|
|
│ ['abca','abc'] │
|
|
└─────────────────────────┘
|
|
```
|
|
|
|
## extractAllGroups(text, regexp) {#extractallgroups}
|
|
|
|
Extracts all groups from non-overlapping substrings matched by a regular expression.
|
|
|
|
**Syntax**
|
|
|
|
``` sql
|
|
extractAllGroups(text, regexp)
|
|
```
|
|
|
|
**Arguments**
|
|
|
|
- `text` — [String](../data-types/string.md) or [FixedString](../data-types/fixedstring.md).
|
|
- `regexp` — Regular expression. Constant. [String](../data-types/string.md) or [FixedString](../data-types/fixedstring.md).
|
|
|
|
**Returned values**
|
|
|
|
- If the function finds at least one matching group, it returns `Array(Array(String))` column, clustered by group_id (1 to N, where N is number of capturing groups in `regexp`).
|
|
|
|
- If there is no matching group, returns an empty array.
|
|
|
|
Type: [Array](../data-types/array.md).
|
|
|
|
**Example**
|
|
|
|
Query:
|
|
|
|
``` sql
|
|
SELECT extractAllGroups('abc=123, 8="hkl"', '("[^"]+"|\\w+)=("[^"]+"|\\w+)');
|
|
```
|
|
|
|
Result:
|
|
|
|
``` text
|
|
┌─extractAllGroups('abc=123, 8="hkl"', '("[^"]+"|\\w+)=("[^"]+"|\\w+)')─┐
|
|
│ [['abc','123'],['8','"hkl"']] │
|
|
└───────────────────────────────────────────────────────────────────────┘
|
|
```
|
|
|
|
## ngrams {#ngrams}
|
|
|
|
Splits the UTF-8 string into n-grams of `ngramsize` symbols.
|
|
|
|
**Syntax**
|
|
|
|
``` sql
|
|
ngrams(string, ngramsize)
|
|
```
|
|
|
|
**Arguments**
|
|
|
|
- `string` — String. [String](../../sql-reference/data-types/string.md) or [FixedString](../../sql-reference/data-types/fixedstring.md).
|
|
- `ngramsize` — The size of an n-gram. [UInt](../../sql-reference/data-types/int-uint.md).
|
|
|
|
**Returned values**
|
|
|
|
- Array with n-grams.
|
|
|
|
Type: [Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md)).
|
|
|
|
**Example**
|
|
|
|
Query:
|
|
|
|
``` sql
|
|
SELECT ngrams('ClickHouse', 3);
|
|
```
|
|
|
|
Result:
|
|
|
|
``` text
|
|
┌─ngrams('ClickHouse', 3)───────────────────────────┐
|
|
│ ['Cli','lic','ick','ckH','kHo','Hou','ous','use'] │
|
|
└───────────────────────────────────────────────────┘
|
|
```
|
|
|
|
## tokens {#tokens}
|
|
|
|
Splits a string into tokens using non-alphanumeric ASCII characters as separators.
|
|
|
|
**Arguments**
|
|
|
|
- `input_string` — Any set of bytes represented as the [String](../../sql-reference/data-types/string.md) data type object.
|
|
|
|
**Returned value**
|
|
|
|
- The resulting array of tokens from input string.
|
|
|
|
Type: [Array](../data-types/array.md).
|
|
|
|
**Example**
|
|
|
|
Query:
|
|
|
|
``` sql
|
|
SELECT tokens('test1,;\\ test2,;\\ test3,;\\ test4') AS tokens;
|
|
```
|
|
|
|
Result:
|
|
|
|
``` text
|
|
┌─tokens────────────────────────────┐
|
|
│ ['test1','test2','test3','test4'] │
|
|
└───────────────────────────────────┘
|
|
``` |