SPARK-SQL内置函数之字符串函数

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1.concat对于字符串进行拼接

concat(str1, str2, …, strN) – Returns the concatenation of str1, str2, …, strN.

Examples:> SELECT concat('Spark', 'SQL');  SparkSQL

2.concat_ws在拼接的字符串中间添加某种格式

concat_ws(sep, [str | array(str)]+) – Returns the concatenation of the strings separated by sep.

Examples:> SELECT concat_ws(' ', 'Spark', 'SQL');  Spark SQL

3.decode转码

decode(bin, charset) – Decodes the first argument using the second argument character set.

Examples: > SELECT decode(encode('abc', 'utf-8'), 'utf-8');   abc

4.encode设置编码格式

encode(str, charset) – Encodes the first argument using the second argument character set.

Examples: > SELECT encode('abc', 'utf-8');abc

5.format_string/printf 格式化字符串

format_string(strfmt, obj, …) – Returns a formatted string from printf-style format strings.

Examples:> SELECT format_string("Hello World %d %s", 100, "days");  Hello World 100 days

6.initcap将每个单词的首字母变为大写,其他字母小写; lower全部转为小写,upper大写

initcap(str) – Returns str with the first letter of each word in uppercase. All other letters are in lowercase. Words are delimited by white space.

Examples:> SELECT initcap('sPark sql');  Spark Sql

7.length返回字符串的长度

Examples:> SELECT length('Spark SQL ');  10

8.levenshtein编辑距离(将一个字符串变为另一个字符串的距离)

levenshtein(str1, str2) – Returns the Levenshtein distance between the two given strings.

Examples:> SELECT levenshtein('kitten', 'sitting');   3

9.lpad返回固定长度的字符串,如果长度不够,用某种字符补全,rpad右补全

lpad(str, len, pad) – Returns str, left-padded with pad to a length of len. If str is longer than len, the return value is shortened to len characters.

Examples:> SELECT lpad('hi', 5, '??');   ???hi

10.ltrim去除空格或去除开头的某些字符,rtrim右去除,trim两边同时去除

ltrim(str) – Removes the leading space characters from str.

ltrim(trimStr, str) – Removes the leading string contains the characters from the trim string

Examples:

> SELECT ltrim(' SparkSQL ');   SparkSQL > SELECT ltrim('Sp', 'SSparkSQLS');   arkSQLS

11.regexp_extract 正则提取某些字符串,regexp_replace正则替换

Examples:> SELECT regexp_extract('100-200', '(\d+)-(\d+)', 1);   100

Examples: > SELECT regexp_replace('100-200', '(\d+)', 'num');   num-num

12.repeat复制给的字符串n次

Examples: > SELECT repeat('123', 2);  123123

13.instr返回截取字符串的位置/locate

instr(str, substr) – Returns the (1-based) index of the first occurrence of substr in str.

Examples:> SELECT instr('SparkSQL', 'SQL');  6

Examples:SELECT locate('bar', 'foobarbar');   4

14.space 在字符串前面加n个空格

space(n) – Returns a string consisting of n spaces.

Examples:> SELECT concat(space(2), '1');  1

15.split以某些字符拆分字符串

split(str, regex) – Splits str around occurrences that match regex.

Examples:> SELECT split('oneAtwoBthreeC', '[ABC]');      ["one","two","three",""]

16.substr截取字符串,substring_index

Examples:

> SELECT substr('Spark SQL', 5);  k SQL > SELECT substr('Spark SQL', -3);  SQL > SELECT substr('Spark SQL', 5, 1);   k
> SELECT substring_index('www.apache.org', '.', 2);   www.apache

17.translate 替换某些字符串为

Examples: > SELECT translate('AaBbCc', 'abc', '123');   A1B2C3

18.get_json_object

get_json_object(json_txt, path) – Extracts a json object from path.

Examples:> SELECT get_json_object('{"a":"b"}', '$.a');  b

19.unhex

unhex(expr) – Converts hexadecimal expr to binary.

Examples:> SELECT decode(unhex('537061726B2053514C'), 'UTF-8');   Spark SQL

20.to_json

to_json(expr[, options]) – Returns a json string with a given struct value

Examples:

> SELECT to_json(named_struct('a', 1, 'b', 2));   {"a":1,"b":2}
> SELECT to_json(named_struct('time', to_timestamp('2015-08-26', 'yyyy-MM-dd')), map('timestampFormat', 'dd/MM/yyyy'));   {"time":"26/08/2015"}
> SELECT to_json(array(named_struct('a', 1, 'b', 2));   [{"a":1,"b":2}]
> SELECT to_json(map('a', named_struct('b', 1)));  {"a":{"b":1}}
> SELECT to_json(map(named_struct('a', 1),named_struct('b', 2)));   {"[1]":{"b":2}}
> SELECT to_json(map('a', 1));  {"a":1}
> SELECT to_json(array((map('a', 1))));  [{"a":1}]

Since: 2.2.0

 

    原文作者:sql
    原文地址: https://www.cnblogs.com/feiyumo/p/8763186.html
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