Import a list of data and apply a function to one of the coordinates?

Questions
,
1

I’m really new on programming and similar things,
I have a data, import on math (with the command data= Import[“PAtht”]) like {{x1,y1},{x2,y2}, etc etc}..
Is it possible to have a new list like {{f(x1),y1},{f(x2),y2}, etc (for example f(x)= a*x^2 with a = parameter )
I mean I wish to have a list of command to transform my data in new data and then plot the new data maybe also with a variable parameter .

Really thanx.

2

One way to do it is with replacement rules:

f[x_] := a x^2;
{{x1, y1}, {x2, y2}, {x3, y3}} /. {x_, y_} :> {f[x], y}

Then you can plot the result with ListPlot.