Re: Mapping A Condition Across Two Different Lists
- To: mathgroup at smc.vnet.net
- Subject: [mg91738] Re: [mg91705] Mapping A Condition Across Two Different Lists
- From: Gregory Lypny <gregory.lypny at videotron.ca>
- Date: Sun, 7 Sep 2008 05:33:26 -0400 (EDT)
- References: <20080906091553.7CU18.147801.imail@eastrmwml41>
Thank you, Jean-Marc and Bob,
Elegant solutions. I find the one with Transpose to be more intuitive
because it's not obvious that Thread is threading the joint
comparison, which it is, and which I guess is another example of
Mathematica's scope.
Regards and thanks again,
Gregory
On Sat, Sep 6, 2008, at 11:56 AM, Jean-Marc Gulliet wrote:
>
> Among other ways, you could map over the transpose of list of the
> two lists, e.g.
>
> In[1]:= targetX = 5; listX = {4, 9, 2, 11, 4};
> targetY = 3; listY = {4, 0, 1, 8, 6};
>
> targetX > #[[1]] && targetY > #[[2]] & /@ Transpose[{listX, listY}]
>
> targetX > #[[1]] || targetY > #[[2]] & /@ Transpose[{listX, listY}]
>
> Out[3]= {False, False, True, False, False}
>
> Out[4]= {True, True, True, False, True}
>
> Best regards,
> -- Jean-Marc
>
On Sat, Sep 6, 2008, at 9:15 AM, Bob Hanlon wrote:
> targetX = 5; listX = {4, 9, 2, 11, 4};
>
> targetY = 3; listY = {4, 0, 1, 8, 6};
>
> Thread[(targetX > # & /@ listX) &&
> (targetY > # & /@ listY)]
>
> {False,False,True,False,False}
>
> targetX > #[[1]] && targetY > #[[2]] & /@
> Transpose[{listX, listY}]
>
> {False,False,True,False,False}
>
> % == %%
>
> True
>
> Thread[(targetX > # & /@ listX) ||
> (targetY > # & /@ listY)]
>
> {True,True,True,False,True}
>
> targetX > #[[1]] || targetY > #[[2]] & /@
> Transpose[{listX, listY}]
>
> {True,True,True,False,True}
>
> % == %%
>
> True
>
>
> Bob Hanlon
>
> ---- Gregory Lypny <gregory.lypny at videotron.ca> wrote:
>
> =============
> Hello everyone,
>
> Not sure how to do this using Map, or even if it's possible.
>
> I can compare a target value to each value in a list like this.
>
> targetX = 5; listX = {4, 9, 2, 11, 4};
> targetX > # & /@ listX
>
> {True, False, True, False, True}
>
> I can do the same for another target and another list.
>
> targetY = 3; listY = {4, 0, 1, 8, 6};
> targetY > # & /@ listY
>
> {False, True, True, False, False}
>
> But can I do it in a similar way for the AND or OR condition without
> having to resort to the Table command?
>
> Table[targetX > listX[[i]] && targetY > listY[[i]], {i, Length@listX}]
>
> {False, False, True, False, False}
>
> Table[targetX > listX[[i]] || targetY > listY[[i]], {i, Length@listX}]
>
> {True, True, True, False, True}
>
> Much obliged,
>
> Gregory
>
>
> --
>
> Bob Hanlon
>