Defining the "iteration" before defining a Table

Questions
1

Hi,

I have 2 functions f[x] and g[x] defined.

I would like to compare them by displaying some values.
So I build two tables :

tbA = Table[f[x],{x,1,4}]

tbB = Table[g[x],{x,1,4}]

Can I define the “iterations” i.e. {x,1,4} before defining the tables, so as I have not to duplicate them?
Thanks for help.

2

Hi Francois

Since Table has the HoldAll attribute this does not work

xRange = {x, 1, 4};

Table[x, xRange]
(* Non-list iterator xRange at position 2 does not evaluate to a real numeric value *)

Have to force evaluation

Table[x, Evaluate@xRange]
(* {1, 2, 3, 4} *)

To keep the range separate from the iteration symbol

range = {1, 4};

Table[x, Evaluate@{x, Splice@range}]
(* {1, 2, 3, 4} *)
3

Thank you !

4

If you need to compare the values, you may try this:

Table[{f[x], g[x]}, {x, 1, 4}] // TableForm
5

@Rohit Namjoshi , @Gianluca Gorni :

I’ve been struggling with this as well. Now I understand why I was struggling, and I have two new techniques to use.