you can also find a detailed explanation in the Qlik help:
ValueList (value {, value })
Returns a set of listed values which, when used in a calculated dimension, will form a synthetic dimension. In charts with a synthetic dimension created with the valuelist function it is possible to reference the dimension value corresponding to a specific expression cell by restating the valuelist function with the same parameters in the chart expression. The function may of course be used anywhere in the layout, but apart from when used for synthetic dimensions it will only be meaningful inside an aggregation function.
Examples:
valuelist ( 1, 10, 100 )
valuelist ( 'a', 'xyz', 55 )
ValueLoop(from [, to [, step = 1 ]])
Returns a set of iterated values which, when used in a calculated dimension, will form a synthetic dimension. The values generated will start with the from value and end with the to value including intermediate values in increments of step. In charts with a synthetic dimension created with the valueloop function it is possible to reference the dimension value corresponding to a specific expression cell by restating the valueloop function with the same parameters in the chart expression. The function may of course be used anywhere in the layout, but apart from when used for synthetic dimensions it will only be meaningful inside an aggregation function.
Examples:
valueloop ( 1, 3 ) returns the values 1, 2 and 3
valueloop ( 1, 5, 2 ) returns the values 1, 3 and 5
valueloop ( 11 ) returns the value 11
