# Concat(A,B,I,J,K)

Concatenates lists or arrays.

When A and B are 1-D arrays,

```Concat(A,B)
```

returns a list (1-D array) consisting of their elements. This form is often used to concatentate two indexes to obtain the elements for a third index.

When A and B are 1-D arrays with a common index

```Concat([A],[B])
```

returns a 2-D array with two columns. Notice square brackets surrounding the variables. If only two parameters are used, column index is .K.

When A and B are arbitrary arrays, where A has index I and B has index J, then

```Concat(A,B,I,J,K)
```

concatenates (i.e., joins) arrays A and B, with the new result indexed by K. You must provide an index K whose length is the sum of the lengths of I and J. Often the index K is obtained using the first form of concatenate.

(new to 4.1) You can omit the K parameter:

```Concat(A,B,I,J)
```

when you do so, the function creates a new local index named K for the result.

Array functions

# Examples

```Index In1 := ['a','b','c']
```
```Concat( In1, ['z'] ) &rarry ['a','b','c','z']
```