Thank you very much! Andrew

Hello Mike,

Thanks very much for your help! I was hoping these new commands would help me sort out the compute logic.

But I am not seeing what I was hoping to see:

• How is "i" counted, from 1 to ? data[[i,1]] is ? data[[i,2]] is ?

Thanks, Andrew

Check out Trace[].

In this case:

data = {{5, 9}, {8, 15}}; 
p[x_] := a x + b; eqns = 
 Trace@Table[
    p[data[[i, 1]]] == data[[i, 2]], {i, 2}] Result : {5 a + b == 9, 
    8 a + b == 15}

Then:

ToString[%] displays:


"{Table[p[data[[i,1]]] == data[[i,2]], {i, 2}] (Result:{5 a + b == 9, \
8 a + b == 15}), {{{{data (Result:{5 a + b == 9, 8 a + b == 15}), \
{{5, 9}, {8, 15}} (Result:{5 a + b == 9, 8 a + b == 15})}, {i \
(Result:{5 a + b == 9, 8 a + b == 15}), 1 (Result:{5 a + b == 9, 8 a \
+ b == 15})}, {{5, 9}, {8, 15}}[[1,1]] (Result:{5 a + b == 9, 8 a + b \
== 15}), 5 (Result:{5 a + b == 9, 8 a + b == 15})}, p[5] (Result:{5 a \
+ b == 9, 8 a + b == 15}), (a 5 + b) (Result:{5 a + b == 9, 8 a + b == \
15}), {(a 5) (Result:{5 a + b == 9, 8 a + b == 15}), (5 a) (Result:{5 \
a + b == 9, 8 a + b == 15})}, (5 a + b) (Result:{5 a + b == 9, 8 a + \
b == 15})}, {{data (Result:{5 a + b == 9, 8 a + b == 15}), {{5, 9}, \
{8, 15}} (Result:{5 a + b == 9, 8 a + b == 15})}, {i (Result:{5 a + b \
== 9, 8 a + b == 15}), 1 (Result:{5 a + b == 9, 8 a + b == 15})}, \
{{5, 9}, {8, 15}}[[1,2]] (Result:{5 a + b == 9, 8 a + b == 15}), 9 \
(Result:{5 a + b == 9, 8 a + b == 15})}, (5 a + b == 9) (Result:{5 a \
+ b == 9, 8 a + b == 15})}, {{{{data (Result:{5 a + b == 9, 8 a + b == \
15}), {{5, 9}, {8, 15}} (Result:{5 a + b == 9, 8 a + b == 15})}, {i \
(Result:{5 a + b == 9, 8 a + b == 15}), 2 (Result:{5 a + b == 9, 8 a \
+ b == 15})}, {{5, 9}, {8, 15}}[[2,1]] (Result:{5 a + b == 9, 8 a + b \
== 15}), 8 (Result:{5 a + b == 9, 8 a + b == 15})}, p[8] (Result:{5 a \
+ b == 9, 8 a + b == 15}), (a 8 + b) (Result:{5 a + b == 9, 8 a + b == \
15}), {(a 8) (Result:{5 a + b == 9, 8 a + b == 15}), (8 a) (Result:{5 \
a + b == 9, 8 a + b == 15})}, (8 a + b) (Result:{5 a + b == 9, 8 a + \
b == 15})}, {{data (Result:{5 a + b == 9, 8 a + b == 15}), {{5, 9}, \
{8, 15}} (Result:{5 a + b == 9, 8 a + b == 15})}, {i (Result:{5 a + b \
== 9, 8 a + b == 15}), 2 (Result:{5 a + b == 9, 8 a + b == 15})}, \
{{5, 9}, {8, 15}}[[2,2]] (Result:{5 a + b == 9, 8 a + b == 15}), 15 \
(Result:{5 a + b == 9, 8 a + b == 15})}, (8 a + b == 15) (Result:{5 a \
+ b == 9, 8 a + b == 15})}, {5 a + b == 9, 8 a + b == 15} (Result:{5 \
a + b == 9, 8 a + b == 15})}"