Mid$
mid$ extracts a sub-string defined by the position and a number of characters out of a CLOB or a string.
mid$(EXP_STRING,EXP_POS,EXP_NB)EXP_STRING is an expression returning a CLOB or string value.EXP_POS is an expression returning an integer value that is the position of the first character to be extracted.EXP_NB is an expression returning an integer value that defines the number of characters to be extracted. # Extraction Of 3 characters from latin alphabetLocal Char ALPHABET(26), DEF(20), WXYZ(20)ALPHABET = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"DEF=mid$(ALPHABET,4,3) : # DEF contains "DEF"WXYZ=mid$(ALPHABET,23,10) : # DEF contains "WXYZ"# inserts a space between every character in a stringMY_TITLE="WELCOME"MY_TITLE=sigma(I=1,len(MY_TITRE),mid$(TITRE,I,1)+" ")# Now MY_TITLE contains "W E L C O M E "The function mid$(EXP_STRING,EXP_POS,EXP_NB) extracts up to EXP_NB characters from the EXP_STRING string starting at the position EXP_POS.
The type of result is Char.
EXP_POS is greater than the length of the string, mid$(EXP_STRING,EXP_POS,EXP_NB) returns the null string "".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).| Error code | Description |
|---|---|
| 10 | The arguments type are not correct. |
| 50 | The position or the length is negative. |