This is my 

```
list = { xp[1]->-0.22245453730291873, xp[2]->0.0308657,xp[3]->0.49903825430681542,xp[4]->-0.491050690290500302,xp[5]->0.21102800632218013,xp[6]->0.0213929,xp[7]->0.28333403464313356,xp[8]->0.0335391,xp[9]->0.31494921279742938,xp[10]->-0.17576685427877437,
  xp[11]->0.0414688,xp[12]->0.31020940567773964,xp[13]->0.32216783070569416,xp[14]->-0.49024347906124188,xp[15]->0.0308204,xp[16]->-0.48930776427295686,xp[17]->0.38781414134352915,xp[18]->-0.42112529129272808,xp[19]->0.032357,xp[20]->-0.229036030243827710,
  xn[1]->-0.24212975266001929,xn[2]->-0.25516397005091557,xn[3]->0.33479444189166097,xn[4]->0.232911190737884438,xn[5]->-0.239542098908387319,xn[6]->0.0169672,xn[7]->0.332092041438385277,xn[8]->-0.245575774654965717,xn[9]->-0.422672696917404833,xn[10]->0.256374664851535206,
  xn[11]->0.39800704049391966,xn[12]->0.253444639060130428,xn[13]->-0.21711686587383844,xn[14]->-0.25412612413695251,xn[15]->-0.248636677542745793,xn[16]->0.25591982468868285,xn[17]->0.22876179760882395,xn[18]->0.29171372603830115,xn[19]->-0.24670297008965947,xn[20]->-0.22931967183419066
}

```

I have to swap the elements within this list. for example:

```
swap[list, xp[[1]], xp[[21]]];

```

meaning I have to interchange the elements of `Xp` and `Xn`, upto all 20 elements of `Xp` and `Xn`. Also I have this same list 15000 different values. So how can I change the value for single list and then use a `Do[]` loop to do this for all other 15000 different files.