SubStr Function

Extract a substring from a string.

Namespace: XSharp.RT
Assembly: XSharp.RT (in XSharp.RT.dll) Version: 2.19

Syntax

 FUNCTION SubStr(
	cTarget,
	nStart,
	nCount
) AS STRING CLIPPER

[ClipperCallingConventionAttribute(new string[] { ... })]
public static string SubStr(
	Usual cTarget = default,
	Usual nStart = default,
	Usual nCount = default
)

Request Example View Source

Parameters

cTarget (Optional): Type: Usual
The string from which to extract a substring.
nStart (Optional): Type: Usual
The starting position in cTarget.
If wStart is positive, it is relative to the leftmost character in cTarget.
If nStart is negative, it is relative to the rightmost character in cTarget.
If nStart is zero, a NULL_STRING is returned.
nCount (Optional): Type: Usual
The number of characters to extract.
If omitted, the substring begins at nStart and continues to the end of the string.
If nCount is greater than the number of characters from nStart to the end of cTarget, the extra is ignored.

Return Value

Type: String
The substring.
If the substring is not present, a NULL_STRING is returned.

Remarks

Substr() is related to the Left() and Right() functions, which extract substrings beginning with leftmost and rightmost characters in cTarget, respectively. The Substr(), Right(), and Left() functions are often used with both the At() and RAt() functions to locate either the first and/or the last position of a substring before extracting it.
They are also used to display or print only a portion of a string.

Examples

These examples extract the first and last name from a variable:

Copy

1cName := "Biff Styvesent"
2? Substr(cName, 1, 4)                // Biff
3? Substr(cName, 6)                    // Styvesent
4? Substr(cName, SLen(cName) + 2)
5// Null string
6? Substr(cName, -9)                    // Styvesent
7? Substr(cName, -9, 3)                // Sty

This example uses Substr() with At() and RAt() to create a function to extract a file name from a file specification:

Copy

1? FileBase("c:\prg\myfile.obj")        // myfile.obj
2FUNCTION FileBase(cFile)
3    LOCAL nPos AS DWORD
4    IF (nPos := RAt("\", cFile)) != 0
5        cFile := Substr(cFile, nPos + 1)
6    ELSEIF (nPos := At(":", cFile)) != 0
7        cFile := Substr(cFile, nPos + 1)
8    ENDIF
9    RETURN cFile

Reference

Functions, Globals and Defines

XSharp.RT Namespace

AtC(String, String)

CharPos(String, DWord)

Left(String, DWord)

RAtLine(String, String)

Right(String, DWord)

Str1(Usual)

SubStr2(String, DWord)

SubStr3(String, DWord, DWord)