Plotting a number line in Mathematica

Question

I would like to plot a simple interval on the number line in Mathematica. How do I do this?

Answer 1

The previous ugly solution has helped me to develop the InequalityPlot function to solve and plotting inequalities in two variables.

InequalityPlot[ineq_, {x_Symbol, xmin_, xmax_},{y_Symbol, ymin_, ymax_},
  opts : OptionsPattern[Join[Options[ContourPlot],
    Options[RegionPlot], {CurvesColor -> RGBColor[1, .4, .2]}]]] :=
 Module[{le = LogicalExpand[ineq], opencurves, closedcurves, curves},
  opencurves = Cases[Flatten[{le /. And | Or -> List}],
   lexp_ < rexp_ | lexp_ > rexp_ | lexp_ < rexp_ | lexpr_ > rexp_ :>
    {lexp == rexp, Dashing[Medium]}];
  closedcurves = Cases[Flatten[{le /. And | Or -> List}],
   lexp_ <= rexp_ | lexp_ >= rexp_ | lexp_ <= rexp_ | lexp_ >= rexp_ :>
    {lexp == rexp, Dashing[None]}];
  curves = Join[opencurves, closedcurves];
  Show[  RegionPlot[ineq, {x, xmin, xmax}, {y, ymin, ymax},
    BoundaryStyle -> None,
    Evaluate[Sequence @@ FilterRules[{opts}, Options[RegionPlot]]]],
   ContourPlot[First[#] // Evaluate, {x, xmin, xmax}, {y, ymin, ymax},
      ContourStyle -> Directive[OptionValue[CurvesColor], Last[#]],
      Evaluate[Sequence @@ FilterRules[{opts},
         Options[ContourPlot]]]] & /@ curves  ]
 ]

Here are two examples:

InequalityPlot[0.5 <= x^2 + y^2 < 1, {x, -1, 1}, {y, -1, 1}]

InequalityPlot[x^2 + y^2 < 0.5 && x + y <= 0.5,{x, -1, 1}, {y, -1, 1}]