vl-string-position (AutoLISP)

Looks for a character with the specified character code in a string

Supported Platforms: Windows and Mac OS

Signature

(vl-string-position char-code str [start-pos [from-end-p]])

char-code

Type: Integer

A numeric value representation of the character to be searched.

str

Type: String

The textual value to be searched.

start-pos

Type: Integer

The position to begin searching from in the string (first character is 0); 0 if omitted.

from-end-p

Type: T or nil

If T is specified for this argument, the search begins at the end of the string and continues backward to pos.

Return Values

Type: Integer or nil

An integer representing the displacement at which char-code was found from the beginning of the string; nil if the character was not found.

Release Information

Releases:

• AutoCAD R14 and later on Windows
• AutoCAD 2011 and later on Mac OS

History

AutoCAD 2021

• char-code argument previously accepted an ASCII character code, but now accepts a Unicode character code.
• 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, (vl-string-position (ascii "€") "中€" 0) previously returned 7, but now returns 1.
• 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.

Examples

(vl-string-position (ascii "z") "azbdc")
1

(vl-string-position 122 "azbzc")
1

(vl-string-position (ascii "x") "azbzc")
nil

The search string used in the following example contains two "z" characters. Reading from left to right, with the first character being displacement 0, there is one z at displacement 1 and another z at displacement 3:

(vl-string-position (ascii "z") "azbzlmnqc")
1

Searching from left to right (the default), the "z" in position 1 is the first one vl-string-position encounters. But when searching from right to left, as in the following example, the "z" in position 3 is the first one encountered:

(vl-string-position (ascii "z") "azbzlmnqc" nil T)
3