@classmethod
def doExpression(cls, vals, ops, getvalues=True):
    """Create an expression string from provided operands and operators"""
    expr = ''
    if getvalues == True:
        for i in range(len(vals)):
            if vals[i] != '':
                vals[i] = float(vals[i])
    if len(ops) > len(vals):
        while len(ops):
            expr += ops.pop(0)
            if len(vals) != 0:
                v = vals.pop(0)
                if v == '':
                    pass
                else:
                    expr += str(v)
    elif len(ops) < len(vals):
        while len(vals):
            v = vals.pop(0)
            if v == '':
                pass
            else:
                expr += str(v)
            if len(ops) != 0:
                expr += ops.pop(0)
    return expr
