You can do this after rendering of the chart in the chart.events.load
method using setCategories
. This code below assumes that each index element on the xAxis has a corresponding data element. If it doesn't then you would need to handle that case.
chart: {
events: {
load: function (event) {
var cats = this.xAxis[0].categories;
var theData = this.series[0].data;
var newCats = [];
for (var i = 0; i < cats.length; i++) {
newCats.push(cats[i] + ' ' + theData[i].y)
}
this.xAxis[0].setCategories(newCats);
}
}
}
Live demo.