I know there is a simple way to do this, but I'm having trouble figuring this out.
How do I combine some text plus a number into one variable that I can use to identify an array?
For example, I want to combine "number" plus "4" to get "number4" so I can identify an array called "number4".
You can use the C preprocessor:
#define MASHUP(text,num) text ## num
MASHUP(number,4)[5] = 0; // Equivalent to number4[5] = 0;
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I have a slight problem because I'm not necessary combining "number" and "4" together. I'm actually combining "number" and "digit1" together, where digit1 is equal to 4.
When I try the MASHUP specified above, it gives me "numberdigit1" not "number4".
Can't be done then. You can't have C evaluate a variable at runtime and use it to form another variable's name.
You're probably doing something that will require multi-dimensional arrays. Rather than referring to a sub-array by name, refer to it by a number.
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Why not make a multidimensional array instead, i.e.
char number[10][10];
number[digit1][whatever] = 5;
How does this get me back the phrase "number4"?
I'm trying to find values in the correct array based on some inputs. For example, if I get 4 for digit1, then I need to pull values from an array called "number4". Surely there must be a way to concatenate these two things.
And those things are called arrays, multi-dimensional ones
Gator,
There is a way to do what you want, but it's not simple. I suspect there is an easier way to accomplish your goal.
However, if you insist on doing that, here's how it could be done:
Declare your arrays.
Define a structure that holds a string pointer and a pointer to an array.
Declare an array of those structures, and initialize it with names and pointers.
Write a function that, given a name and a number, creates a string from those two, searches the array of structures, and returns the corresponding array pointer.
For example:
int array1[10];
int array2[10];
int array3[10];
struct array_entry
{
char *array_name;
int *array_ptr;
};
struct array_entry arrays[] =
{
{"number1",array1},
{"number2",array2},
{"number3",array3}
};
const int num_arrays = sizeof(arrays) / sizeof(struct array_entry);
The remainder is left as an exercise for the reader. 
Regards,
-Mike
How does this get me back the phrase "number4"?
If what you have now looks like:
char number1[][] = { { ... } };
char number2[][] = { { ... } };
you may consider replacing it with
char number[][][] = { { { ... } } };
so that your choice of number is just another dimension of the array rather than a new name of the array.
[edit]Ooops, I miss read the question at the start.
Please disregard what I said in the post
What you are looking for is sprintf().
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1279788631/#3
[/edit]
What you are looking for is sprintf().
No, I really don't think it is.
Andrew