Hello. I'm having a little difficulty understanding the behavior of the Characters function when I apply a set of rules to it. Let me explain. I can apply it like I have below to create lists of the constituent characters in a string in two different ways producing the same output as shown below. In[1]:= a=Characters["fish"] b="fish" // Characters Out[1]= {"f", "i", "s", "h"} Out[2]= {"f", "i", "s", "h"}

Both ways of applying the function give the same output. In[3]:= a==b Out[3]= True

However, when I apply a rule to both expressions above, only one takes the change. In[4]:= Characters["fish"]/. {"f" -> "d"} "fish" // Characters/. {"f" -> "d"} Out[4]= {"d", "i", "s", "h"} Out[5]= {"f", "i", "s", "h"}

If I apply the same rule to the variables set at the top, the rule is applied in both cases. In[6]:= a/. {"f" -> "d"} b/. {"f" -> "d"} Out[6]= {"d", "i", "s", "h"} Out[7]= {"d", "i", "s", "h"}

My question is shouldn't "fish"//Characters/.{"f"->"d"} produce {d,i,s,h}? And if not, what is it that I am missing or not getting?

I have attached this post as a notebook as well.

Thanks. Philip.

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