substr (AutoLISP)

Returns a substring of a string

Supported Platforms: Windows, Mac OS, and Web

Signature

(substr str start [length])

str

Type: String

A textual value.

start

Type: Integer

A positive numeric value indicating the starting position in str. The first character in the string is position 1.

length

Type: Integer

A positive numeric value specifying the number of characters to search through in str. If length is not specified, the substring continues to the end of str.

Return Values

Type: String

A substring from str.

Remarks

The substr function starts at the start character position of str and continues for length characters.

Note: The first character of str is character number 1. This differs from other functions that process elements of a list (like nth and ssname) that count the first element as 0.

Release Information

Releases:

AutoCAD R12 and later on Windows
AutoCAD 2011 and later on Mac OS

History

AutoCAD 2021

str argument previously accepted an ASCII text string or character, but now accepts a Unicode text string or character.
Return value was modified to support Unicode characters and might be different than earlier releases. In earlier releases, the length of a Unicode character was improperly calculated. For example, (substr "中国" 1 1) previously returned "\\", but now returns "中".
LISPSYS system variable controls which AutoLISP engine is used and the behavior of the function.
- 0 - ASCII character support (legacy behavior)
- 1 or 2 - Unicode character support
Note: After the value of the LISPSYS system variable has been changed, AutoCAD must be restarted for the change to take affect.

Example

(substr "abcde" 2)
"bcde"

(substr "abcde" 2 1)
"b"

(substr "abcde" 3 2)
"cd"

(substr "€abc€" 4 2)
"c€"

(substr "中国" 1 1) 
"中"