Expression1 | Real2 | → | Item3 |
The EXSUB operation is used to retrieve a portion of an expression. The real argument identifies the subexpression in the expression to retrieve. An expression is a sequence of real numbers, complex numbers, symbols and operations. If you read your expression from left to right, the left most item in that sequence is 1 and each item after that is the next number in the sequence. If the item at this offset is a real number, complex number or symbol, then the subexpression is that item itself. If the item at this offset is an operation, then the subexpression is the operation and its arguments.
So, for the expression 'SIN(X+10)', the subexpressions are:
Index | Subexpression |
---|---|
1 | 'SIN(X+10)' Expression |
2 | Symbol X |
3 | 'X+10' Expression |
4 | Real Number 10 |
The result of EXSUB is a real number, complex number, symbol or expression depending on what the subexpression is at that index. In the example able, EXGET would return 'X+10' if you look for the third subexpression.