For each..next
The for each..next control statement is a script iteration construct which executes one or several statements for each value in a comma separated list. The statements inside the loop enclosed by for and next will be executed for each value of the list.
Syntax:
Special syntax makes it possible to generate lists with file and directory names in the current directory.
for each var in list
[statements]
[exit for [ ( when | unless ) condition ]
[statements]
next [var]
Arguments:
| Argument | Description |
|---|---|
| var | A script variable name which will acquire a new value from list for each loop execution. If var is specified after next it must be the same variable name as the one found after the corresponding for each. |
The value of the var variable may be changed by statements inside the loop, but this is not good programming practice.
If an exit for clause is encountered inside the loop, the execution of the script will be transferred to the first statement after the next clause denoting the end of the loop. An exit for clause can be made conditional by the optional use of a when or unless suffix.
Syntax:
list := item { , item }
item := constant | (expression) | filelist mask | dirlist mask | fieldvaluelist mask
| Argument | Description |
|---|---|
| constant | Any number or string. Note that a string written directly in the script must be enclosed by single quotes. A string without single quotes will be interpreted as a variable, and the value of the variable will be used. Numbers do not need to be enclosed by single quotes. |
| expression | An arbitrary expression. |
| mask |
A filename or folder name mask which may include any valid filename characters as well as the standard wildcard characters, * and ?. You can use absolute file paths or lib:// paths. |
| condition | A logical expression evaluating to True or False. |
| statements | Any group of one or more Qlik Sense script statements. |
| filelist mask |
This syntax produces a comma separated list of all files in the current directory matching the filename mask. |
| dirlist mask |
This syntax produces a comma separated list of all folders in the current folder matching the folder name mask. |
| fieldvaluelist mask | This syntax iterates through the values of a field already loaded into Qlik Sense. |
Example 1: Loading a list of files
Example 2: Creating a list of files on disk
This example loads a list of all Qlik Sense related files in a folder.
Example 3: Iterating through a the values of a field
This example iterates through the list of loaded values of FIELD and generates a new field, NEWFIELD. For each value of FIELD, two NEWFIELD records will be created.
The resulting table looks like this:
| NEWFIELD |
|---|
| one-1 |
| one-2 |
| two-1 |
| two-2 |
| three-1 |
| three-2 |