I want to control a slider value with a number in a text layer. The below expression works in my composition. However, I want to keyframe it so the first keyframe is zero and the second keyframe corresponds to the value set by the text layer in the expression ("Number").
Is there any way to modify this expression so it only attaches to the second keyframe, leaving my first keyframe value set to zero?
if (! isNaN(parseFloat(txt)))