INSERT

INSERT (LET)

Let Subcommand

Insert the contents of one variable into another variable at a specified row location.

The motivation for this command is the following. Suppose we have
LET U1 = UNIFORM RANDOM NUMBERS FOR I = 1 1 10
LET U2 = UNIFORM RANDOM NUMBERS FOR I = 1 1 5


and we want to replace rows 6 to 10 of U1 with the values in U2. The INSERT command can be used do this.

There are two cases for INSERT. In the above example, the values of U2 overwrite the current contents of U1. Alternatively, you can request that the values of U2 be added at the specified location but that the values of U1 are not overwritten. That is, the output variable will have rows 1 to 5 of U1, then rows 6 to 10 will have the U2 values, and then rows 11 to 16 will be rows 6 to 10 of U1.

To specify that values of the first variable will be overwritten (the default), enter

SET INSERT OVERWRITE ON

To specify that the values of the second variable will be inserted and the values of the first variable will be shifted rather than overwritten, enter

SET INSERT OVERWRITE OFF

When the two variables are the same length and we are replacing corresponding rows of the first variable with the second variable, an appropriate SUBSET or FOR clause can typically be used. When the values of the second variable are added to either the beginning or end of the first variable, then the APPEND, EXTEND or COMBINE commands can be used. The INSERT command is useful when the contents of the second variable are inserted at an arbitrary location of the first variable.

LET <y3> = INSERT <y1> <y2> <nloc>
where <y1> is the first response variable;
            <y2> is the second reponse variable;
            <nloc> is a parameter that defines the starting row in <y1> where the <y2> values will be inserted;
and       <y3> is the output variable.

The <y1> and <y2> variables do not need to be the same length. The <y3> variable will be at least the same length as <y1> (it can be longer).

If the value of <nloc> is non-positive or greater than the length of <y1> an error will be returned and <y3> will not be created.

The <y3> variable can be the same as <y1>.

LET NLOC = 50
LET Y1 = INSERT Y1 Y2 NLOC

None

None

APPEND	=	Append a variable to the end of another variable.
EXTEND	=	Extend a variable by another variable.
COMBINE	=	Combine one or more variables and parameters into a single variable.

Data Management

2020/02

 
let u1 = uniform random numbers for i = 1 1 10
let u2 = uniform random numbers for i = 1 1 10
let nloc = 6
let u1 = insert u1 u2 nloc
print u1
    

The following output is generated

---------------
             U1
---------------
         0.5005
         0.8613
         0.0378
         0.0261
         0.4440
         0.5309
         0.1099
         0.2967
         0.6300
         0.6134
    

let u1 = uniform random numbers for i = 1 1 10
let u2 = uniform random numbers for i = 1 1 10
set insert overwrite off
let nloc = 6
let u1 = insert u1 u2 nloc
print u1
    

The following output is generated

---------------
             U1
---------------
         0.5005
         0.8613
         0.0378
         0.0261
         0.4440
         0.5309
         0.1099
         0.2967
         0.6300
         0.6134
         0.4243
         0.7259
         0.8519
         0.0964
         0.3348