command for extracting data??

can someone explain this command x1a = x1(1:end-tau-dt); i'm really confuse with this line in my function where tau = 1 dt = 1 but what is meaning of "end" here please some one explain me.

Answer 1

[madhan ravi]

simple example see indexing for better understanding

 >> x1 = 1:10
  tau =1
  dt = 1
  a = x1(1:end-tau-dt)

x1 =

       1     2     3     4     5     6     7     8     9    10

tau =

       1

dt =

       1

a =

       1     2     3     4     5     6     7     8

>>

[madhan ravi]

end represent the last index of an array so 10-1-1 ==>8 so elements from 1 to 8 are extracted from the vector x1 it also simply represents

x1(1:8)

Answer 2

[Bruno Luong]

'end' when used in array indexing is replaced by size(x1,n), where n is the dimension where the 'end' appears.

Here in your case it is x1(1:size(x1,2)-tau-dt), so it is indexed from 1 to ( tau+dt) before the last element.