Using All in MapAt in Mathematica

Question

I often have a list of pairs, as

data = {{0,0.0},{1,12.4},{2,14.6},{3,25.1}}

and I want to do something, for instance Rescale, to al

Answer 1

Here is another approach:

op[data_List, fun_] := 
 Join[data[[All, {1}]], fun[data[[All, {2}]]], 2]

op[data, Rescale]

Edit 1:

An extension from Mr.Wizard, that does not copy it's data.

SetAttributes[partReplace, HoldFirst]
partReplace[dat_, func_, spec__] := dat[[spec]] = func[dat[[spec]]];

used like this

partReplace[data, Rescale, All, 2]

Edit 2: Or like this

ReplacePart[data, {All, 2} -> Rescale[data[[All, 2]]]]