Loops

[Vikash938]

what are loops in Qlik Sense and explain with example how it works?

[seanbruton · Accepted solution]

⭐What Are Loops in Qlik Sense?

In the Qlik Sense Data Load Editor, a loop is a control-flow structure that repeats a section of script multiple times.

Qlik's scripting language supports three types of loops:

Loop Type	Purpose
FOR … NEXT	Loop over numeric ranges, counters, lists, or field values
DO … LOOP	Loop until a condition is met
WHILE modifier	Add a repeat condition

Why Use Loops? (Use Cases)

Loops are used in Qlik Sense for tasks that require repeated execution, such as:

1. Loading multiple similar files

Example: loading monthly CSV files named Sales_2024_01.csv, Sales_2024_02.csv, etc.

1. Generating dates or time periods

Example: iterating through years, months, days.

1. API pagination (REST calls)

Loop until "nextPage" is empty.

1. Dynamic or iterative transformations

Example: creating multiple calendars or loading repeated structures.

1. Building variable lists and metadata

Example: iterating through table fields.

🟦WORKING EXAMPLE 1 — Single Loop

Scenario

You have 12 monthly sales files:

Sales_2024_01.csv

Sales_2024_02.csv

Sales_2024_12.csv

You want to load them all without writing 12 separate LOAD statements.

Script — Single FOR Loop

FOR i = 1 to 12

    LET vMonth = Num(i, '00');   // Formats 1 → 01, 2 → 02 …

    LET vFile  = 'lib://Data/Sales_2024_' & vMonth & '.csv';

    Sales:

    LOAD *

    FROM $(vFile)

    (txt, utf8, embedded labels, delimiter is ',', msq);

NEXT i;

How it works

• The loop runs 12 times.
• Each time, Qlik builds a filename like Sales_2024_03.csv.
• Data is appended into the Sales table automatically.

🟦WORKING EXAMPLE 2 — Nested Loops (Loop in a Loop)

Scenario

You have sales files for multiple years and months:

Sales_2023_01.csv … Sales_2023_12.csv

Sales_2024_01.csv … Sales_2024_12.csv

Sales_2025_01.csv … Sales_2025_12.csv

You want Qlik Sense to automatically load 3 years × 12 months = 36 files

Script — Loop Inside a Loop

FOR year = 2023 to 2025

    FOR month = 1 to 12

        LET vMonth = Num(month, '00');

        LET vFile  = 'lib://Data/Sales_' & year & '_' & vMonth & '.csv';

        Sales:

        LOAD

            *,

            $(year)    AS Year,

            $(vMonth)  AS Month

        FROM $(vFile)

        (txt, utf8, embedded labels, delimiter is ',', msq);

    NEXT month;

NEXT year;

How it works

• Outer loop iterates through years (2023 → 2025)
• Inner loop iterates through months (01 → 12)
• Every combination generates a file path like:

Sales_2024_07.csv

Sales_2025_12.csv

• Each load appends into one final Sales table.

🟦 Additional Loop Types in Qlik (for completeness)

1. DO…LOOP UNTIL

LET i = 1;

DO

    TRACE Loop iteration $(i);

    LET i = i + 1;

LOOP UNTIL i > 5;

1. FOR EACH (files, variables, inline lists)

FOR EACH file IN FileList('lib://Data/*.csv')

    LOAD * FROM $(file);

NEXT file;

🎯Summary

Loop Type	When to Use
FOR … NEXT	Numeric ranges, counters, dates
FOR EACH	Iterating over file lists or variables
DO … LOOP UNTIL	Continue until a condition is met
Nested Loops	Multi-dimension iteration (years × months etc.)

Loops are extremely useful in dynamic data loading, eliminating repetitive scripts and making Qlik apps maintainable.