String length: length

Syntax

length ( op )

Input parameters

op	the operand

Examples of valid syntaxes

length("Hello, World!")
length(DS_1)

Semantics for scalar operations

Returns the length of a string. For example:

length("Hello, World!") gives 13

length("") gives 0

Input parameters type

op

dataset { measure<string> _+ }
| component<string>
| string

Result type

result

dataset { measure<integer[value >= 0]> int_var }
| component<integer[value >= 0]>
| integer[value >= 0]

Additional Constraints

For operations at Data Set level, the input Data Set must have exactly one string type Measure.

Behaviour

The operator has the behaviour of the “Operators changing the data type” (see the section “Typical behaviours of the ML Operators”). If op is a Data Set then length returns a dataset with a single measure int_var of type integer.

Examples

Given the operand dataset DS_1:

Input DS_1 (see structure)

Id_1	Id_2	Me_1
1	A	hello
2	B

Input DS_2 (see structure)

Id_1	Id_2	Me_1	Me_2
1	A	hello	world
2	B		hi

Example 1

DS_r := length(DS_1);

results in (see structure):

DS_r
Id_1	Id_2	int_var
1	A	5
2	B	0

Example 2

DS_r:= DS_1[calc Me_2:=length(Me_1)];

results in (see structure):

DS_r
Id_1	Id_2	Me_1	Me_2
1	A	hello	5
2	B		0

Example 3

DS_r := DS_2 [calc Me_10:= length(Me_1), Me_20:=length(Me_2)];

results in (see structure):

DS_r
Id_1	Id_2	Me_1	Me_2	Me_10	Me_20
1	A	hello	world	5	5
2	B		hi	0	2

Example 4

length operator applied at Data Set level to a multi Measure Data Set:

DS_r := length(DS_2)

would give error because DS_2 has more than one Measure.