How Peek() function works - detailed explanation

[Sonja_Bauernfeind]

The peek function uses the following syntax :

Peek( field_name [, row_no[, table_name ] ])

• Only the field_name is mandatory.
• row_no and table_name are optional parameters.
• Table_name has a dependency with row_no, which means that table_name cannot be used without row_no.

Source: Peek - script function 

Environment

• Qlik Sense Enterprise on Windows 
• Qlik Sense Business 
• Qlik Cloud 

Resolution

Example:

EmployeeDates:
Load * Inline [
EmployeeCode|StartDate|EndDate
101|02/11/2010|23/06/2012
102|01/11/2011|30/11/2013
103|02/01/2012|
104|02/01/2012|31/03/2012
105|01/04/2012|31/01/2013
106|02/11/2013|
] (delimiter is '|');

let test = Peek('EmployeeCode',-2,'EmployeeDates') ; -> Correct, both row_no and table_name are being used at the same time
trace $(test); result = 105
let test1 = Peek('EmployeeCode') ; -> Correct, if no row is stated, -1 is assumed and if no table_name is stated, the current table is assumed.
trace $(test1); result = 106
let test2 = Peek('EmployeeCode',0) ; -> Correct, if no table_name is stated, the current table is assumed.
trace $(test2);  result = 101
let test3 = Peek('EmployeeCode','EmployeeDates') ; -> Incorrect, row_no is not being specified in this case.
trace $(test3);  result = NULL