Re: strange behavior with Map

*To*: mathgroup at smc.vnet.net*Subject*: [mg116401] Re: strange behavior with Map*From*: Bill Rowe <readnews at sbcglobal.net>*Date*: Sun, 13 Feb 2011 03:07:39 -0500 (EST)

On 2/12/11 at 5:20 AM, robertr at math.uh.edu (Robert Rosenbaum) wrote: >This doesn't seem right: >In[181]:= Map[Function[x, 2], {{1, 2}, {1, 2}}, 2] >Out[181]= {2, 2} >In[180]:= Map[Function[x, 0 x + 2], {{1, 2}, {1, 2}}, 2] >Out[180]= {{2, 2}, {2, 2}} What were you expecting? Note In[52]:= Function[x, 2][{1, 2}] Out[52]= 2 since this function replaces any argument with 2. But In[53]:= Function[x, 0 x + 2][{1, 2}] Out[53]= {2,2} since this function multiplies the list by 0 then adds 2 which means the result will have the same number of elements as the input when the input is a list. Perhaps you meant to map the function to only level 2 rather than levels 1 through 2? That is In[54]:= Map[Function[x, 2], {{1, 2}, {1, 2}}, {2}] Out[54]= {{2, 2}, {2, 2}}