# Question about ordered pairs and dictionaries.

Hello, what I am trying to do is use (math) functions within functions that are defined by ordered pairs. The code I have looks like this:

 f = {-3:4, -2:2, -1:0, 0:1, 1:3, 2:4, 3:-1} g = {-3:-2, -2:0, -1:-4, 0:0, 1:-3, 2:1, 3:2} show(g[f[g[0]]]) 

So, the way I intend for this to work is g[0] should return 0, which will become f[0] which returns 1, which becomes g[1] which should return -3. When I try to run this in sage 5.4, nothing appears to happen. Any help would be really great, thanks!

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Hi, the code above seems fine, the output of the show function was a pdf file containing -3. Maybe just

f = {-3:4, -2:2, -1:0, 0:1, 1:3, 2:4, 3:-1}
g = {-3:-2, -2:0, -1:-4, 0:0, 1:-3, 2:1, 3:2}
g[f[g[0]]]


If you want the result printed then

f = {-3:4, -2:2, -1:0, 0:1, 1:3, 2:4, 3:-1}
g = {-3:-2, -2:0, -1:-4, 0:0, 1:-3, 2:1, 3:2}
print g[f[g[0]]]

more

I really appreciate you checking it, but strangely enough, now when I try evaluating the above code I get an error: Traceback (most recent call last): File "<stdin>", line 1, in <module> File "_sage_input_3.py", line 8, in <module> _interact_.SAGE_CELL_ID=1 NameError: name '_interact_' is not defined

( 2012-11-16 14:42:14 -0500 )edit

The code in your question contains a syntax error and I can't edit it. I'll update the answer above to include it.

( 2012-11-16 14:57:03 -0500 )edit