Mid$

mid$ extracts a sub-string defined by the position and a number of characters out of a CLOB or a string.

Syntax

   mid$(EXP_STRING,EXP_POS,EXP_NB)

• EXP_STRING is an expression returning a CLOB or string value.
• EXP_POS is an expression returning an integer value that is the position of the first character to be extracted.
• EXP_NB is an expression returning an integer value that defines the number of characters to be extracted.

Examples

   # Extraction Of 3 characters from latin alphabet
   Local Char ALPHABET(26), DEF(20), WXYZ(20)
   ALPHABET = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
   DEF=mid$(ALPHABET,4,3) : # DEF contains "DEF"
   WXYZ=mid$(ALPHABET,23,10) : # DEF contains "WXYZ"

   # inserts a space between every character in a string
   MY_TITLE="WELCOME"
   MY_TITLE=sigma(I=1,len(MY_TITRE),mid$(TITRE,I,1)+" ")
   # Now MY_TITLE contains "W E L C O M E "

Description

The function mid$(EXP_STRING,EXP_POS,EXP_NB) extracts up to EXP_NB characters from the EXP_STRING string starting at the position EXP_POS.

The type of result is Char.

Comments

• If EXP_POS is greater than the length of the string, mid$(EXP_STRING,EXP_POS,EXP_NB) returns the null string "".
• If EXP_NB is greater than the number of remaining characters, only the remaining characters will be extracted, and the length of the result is smaller than EXP_NB.
• mid$(EXP_STRING,EXP_POS,EXP_NB) is equivalent to seg$(EXP_STRING,EXP_POS+EXP_NB-1).

Associated errors

See also

right$, left$, seg$, len.