# CoCoA:Len

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## Len

the length of an object

### Description

This function returns the length of an object, as summarized in

the table below:

<verbatim>

```     ----------------------------------------------
| type   | length                              |
-----------------------------------------------|
| IDEAL  | length of Gens(E)                   |
| INT    | 1                                   |
| LIST   | number of items in the list         |
| MAT    | number of rows of the matrix        |
| MODULE | length of Gens(E)                   |
| POLY   | number of monomials                 |
| RATFUN | if E=F/G, then Len(E)=Len(F)+Len(G) |
| VECTOR | number of components                |
----------------------------------------------
The operator Len
```

</verbatim>

#### Example

```  Use R ::= Q[x,y];
L := [<quotes>a</quotes>,2,3,[4,5]];
Len(L);
4
-------------------------------
Len(L[1]);
1
-------------------------------
Len(L[4]);
2
-------------------------------
Len(x^2 + xy + y^2 + xy^4);
4
-------------------------------
Len((x^2+y^2)/(x+y+y^2));
5
-------------------------------
Len((x+y) - (xy/x));
1
-------------------------------
Len(Ideal(x,x^2));
2
-------------------------------
```

The function <ttref>Size</ttref> returns the amount of memory used by the object.

### Syntax

```Len(E:OBJECT):INT
```

```   <type>ideal</type>
<type>integer</type>
<type>list</type>
<type>matrix</type>
<type>module</type>
<type>polynomial</type>
<type>ratfun</type>
<type>vector</type>
```