Split text by symbol

Split text by symbol (another string, also called delimiter or separator)

Approaches

list of equivalent approaches to split text by symbol

• MySQL: MySQL SUBSTRING_INDEX() function - w3resource
• Excel: (1) parse data (資料剖析) only allowed one character used as separator! (2) LEFT, RIGHT, FIND, LEN (3) MOD, FIND, LEN
• PHP: explode or preg_split function

Example

Task: Split the position e.g. 25.040215, 121.512532 by the comma ( , ) to obtain the latitude (1st string) and longitude (2nd string).

Expected output:

• 25.040215
• 121.512532

MySQL Approach

Only one symbol was allowed. The following query will get the last element if there are more than two symbols.

1. to get the first string ( 25.040215 ): SELECT TRIM(SUBSTRING_INDEX('25.040215, 121.512532' ,',', 1))
2. to get the second string ( 121.512532 ): SELECT TRIM(SUBSTRING_INDEX('25.040215, 121.512532' ,',', -1))

Live demo on SQL Fiddle

CREATE TABLE tbl(str varchar(50));
INSERT INTO tbl VALUES('25.040215, 121.512532');
INSERT INTO tbl VALUES('25.040215, 121.512532, 999.999'); /*bad data: 2 or more symbols*/
INSERT INTO tbl VALUES('123.456'); /*bad data: no symbol exists*/
SELECT TRIM(SUBSTRING_INDEX(str ,',', 1)), TRIM(SUBSTRING_INDEX(str ,',', -1)) FROM tbl WHERE str LIKE '%,%';

Excel Approach

Comparison of approaches

Approach	Output
Approach 1: Parse data	Multiple parts will be returned if the content contains two or more separator characters.
Approach 2: SUBSTRING_INDEX	Only two parts will be returned if the content contains two or more separator characters.

Approach 1: Pparse data

parse data (資料剖析)

• instruction with screenshots: Split text into different cells - Excel

Approach 2: SUBSTRING_INDEX

	A	B	C
1	25.040215, 121.512532	25.040215	121.512532

If the data set is perfect

1. separator character: ,
2. to get the first string ( 25.040215 ): B1 = MID( A1, 1, FIND(",", A1)-1)
3. to get the second string ( 121.512532 ): C1 = MID( A1, FIND(",", A1)+1, LEN(A1))

if the data set was mixed with empty values. Return empty if the value is empty.

1. to get the first string ( 25.040215 ): B1 = IF(ISERROR(MID(A1, 1, FIND(",", A1)-1)), "", MID(A1, 1, FIND(",", A1)-1))
2. to get the second string ( 121.512532 ): C1 = IF(ISERROR(TRIM(MID(A1, FIND(",", A1)+1, LEN(A1)))), "", TRIM(MID(A1, FIND(",", A1)+1, LEN(A1)))

online demo (allow to edit)

PHP Approach

PHP script

$input_string = "25.040215, 121.512532";

$list1 = explode(",", $input_string);
$trimmed_list1 = array_map('trim', $list1);


$list2 = preg_split("/[\s,]+/", $input_string);


print_r($trimmed_list1);
print_r($list2);

output

Array ( 
  [0] => 25.040215 
  [1] => 121.512532 
)