Is it possible to extract n-th part of an expression as a string, without any evaluation?
For example,

In[1]   x=1;y=2;z=3;
In[2]   SomeCode[Plus[x,y,z], 2]
Out[2]  "y" (* y as a string! *)

I've tried

  In[2] Defer[Unevaluated[Plus[x,y,z]][[2]]]

but failed :

  Out[2] Unevaluated[Plus[x, y, z]][[2]] (* fail *)
  • $\begingroup$ As far as I can tell, y would not be a string if you pulled it from the example expression. Instead, you would need to somehow have it be changed to a string. $\endgroup$ Mar 21, 2021 at 13:58

1 Answer 1


One way of doing this is to use Extract with Hold and Unevaluated to make it into a string, like:

x = 1; y = 2; z = 3;
t = Extract[Hold[Plus[x, y, z]], {1, 2}, Hold ];
t /. Hold[y_] -> ToString[Unevaluated[y]]

(* y *)
  • 2
    $\begingroup$ +1. Similar: Construct[ToString, Extract[Hold[Plus[x, y, z]], {1, 2}, Unevaluated]]. Another variation close to the OP's initial attempt: Extract[Unevaluated[Plus[x, y, z]], 2, Defer]. $\endgroup$
    – WReach
    Mar 21, 2021 at 16:18

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