SubField - script and chart function

SubField() is used to extract substring components from a parent string field, where the original record fields consist of two or more parts separated by a delimiter.

The Subfield() function can be used, for example, to extract first name and surname from a list of records consisting of full names, the component parts of a path name, or for extracting data from comma-separated tables.

If you use the Subfield() function in a LOAD statement with the optional field_no parameter left out, one full record will be generated for each substring. If several fields are loaded using Subfield() the Cartesian products of all combinations are created.

Syntax:

SubField(text, delimiter[, field_no ])

Return data type: string

Arguments:

Argument	Description
text	The original string. This can be a hard-coded text, a variable, a dollar-sign expansion, or another expression.
delimiter	A character within the input text that divides the string into component parts.
field_no	The optional third argument is an integer that specifies which of the substrings of the parent string text is to be returned. Use the value 1 to return the first substring, 2 to return the second substring, and so on. A negative value causes the substring to be extracted from the right-hand side of the string. That is, the string search is from right to left, instead of left to right, if field_no is a positive value.

SubField() can be used instead of using complex combinations of functions such as Len(), Right(), Left(), Mid(), and other string functions.

Example

Result

SubField(S, ';' ,2)

Returns 'cde' if S is 'abc;cde;efg'.

SubField(S, ';' ,1)

Returns NULL if S is an empty string.

SubField(S, ';' ,1)

Returns an empty string if S is ';'.

Add the example script to your app and run it. Then add, at least, the fields listed in the results column to a sheet in your app to see the result.

FullName:

LOAD * inline [

Name

'Dave Owen'

'Joe Tem'

];

SepNames:

Load Name,

SubField(Name, ' ',1) as FirstName,

SubField(Name, ' ',-1) as Surname

Resident FullName;

Drop Table FullName;

Name	FirstName	Surname
Dave Owen	Dave	Owen
Joe Tem	Joe	Tem

Suppose you have a variable that holds a path name vMyPath,

Set vMyPath=\Users\ext_jrb\Documents\Qlik\Sense\Apps;.

In a text & image chart, you can add a measure such as:
SubField(vMyPath, '\',-3), which results in 'Qlik', because it is the substring third from the right-hand end of the variable vMyPath.

This example shows how using multiple instances of the Subfield() function, each with the field_no parameter left out, from within the same LOAD statement creates Cartesian products of all combinations. The DISTINCT option is used to avoid creating duplicate record.

Add the example script to your app and run it. Then add, at least, the fields listed in the results column to a sheet in your app to see the result.

LOAD DISTINCT

Instrument,

SubField(Player,',') as Player,

SubField(Project,',') as Project;

Load * inline [

Instrument|Player|Project

Guitar|Neil,Mike|Music,Video

Guitar|Neil|Music,OST

Synth|Neil,Jen|Music,Video,OST

Synth|Jo|Music

Guitar|Neil,Mike|Music,OST

] (delimiter is '|');

Instrument	Player	Project
Guitar	Mike	Music
Guitar	Mike	Video
Guitar	Mike	OST
Guitar	Neil	Music
Guitar	Neil	Video
Guitar	Neil	OST
Synth	Jen	Music
Synth	Jen	Video
Synth	Jen	OST
Synth	Jo	Music
Synth	Neil	Music
Synth	Neil	Video
Synth	Neil	OST

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