`strextract(X;P;N)`

Returns the specified number of characters, starting at a certain position, extracted from a given string.

Syntax

strextract(X;P;N)
bstrextract(X;P;N)

Argument Type Description

Argument	Type	Description
`X`	text	The string on which to apply the function A scalar value or the name of a column
`P`	integer	An index corresponding to a particular position in `X` The index `P` is 1-based (i.e., the first character has position 1). A negative position counts back from the end of the string (i.e., `P`=`-1` refers to the last character).
`N`	integer	The number of characters to extract from `X` `N`=`-1` refers to as many characters as necessary to reach the end of the string. If `N` is N/A, it is treated as -1.

X

text

The string on which to apply the function

A scalar value or the name of a column

P

integer

An index corresponding to a particular position in X

The index P is 1-based (i.e., the first character has position 1).

A negative position counts back from the end of the string (i.e., P=-1 refers to the last character).

N

integer

The number of characters to extract from X

N=-1 refers to as many characters as necessary to reach the end of the string.

If N is N/A, it is treated as -1.

Returns the text value consisting of N characters beginning at position P extracted from the string X.

If X or P is N/A, the result is N/A.


`value`	`position`	`number`	`strextract(value;position;number)`
'testing'	2	3	'est'
'testing'	-5	-1	'sting'

strextract is Unicode (UTF-8) compliant and will work with Unicode or plain ASCII text fields.
If passed a string argument that is not legal Unicode, it will by default signal an error (configurable as a user preference).
A corresponding function bstrextract can be used with non-Unicode strings (e.g., binary or legacy encodings).