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Purpose |
Search a
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Syntax |
y& = INSTR([Position&,] MainStr$, [ANY] MatchStr$) |
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Remarks |
INSTR returns the position of MatchStr$ within MainStr$. The return value is indexed to one, while zero means "not found". Position& specifies the character position to begin the search. If Position& is one or greater, MainStr$ is searched left to right. The value one starts at the first character, two the second, etc. If Position& is -1 or less, MainStr$ is searched from right to left. The value -1 starts at the last character, -2 the second to last, etc. If Position& is not given, the default value of +1 is assumed. x& = INSTR("xyz", "y") ' returns 2 x& = INSTR("xyz", "a") ' returns 0 a$ = "My Dog" : b$ = " " x& = INSTR(a$, b$) ' returns 3 It is important to note that in all cases, even when Position& is negative, the return value of INSTR() is the absolute position of the match, from left to right, starting with the first character. |
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ANY |
If the ANY keyword is included, MatchStr$ specifies a list of single characters. INSTR searches for each of these characters individually. As soon as any one of these characters is found, INSTR returns the position of the match. x& = INSTR(-2, "efcdef", ANY "ef") returns a result of 5 INSTR is case-sensitive, meaning that upper-case and lower-case letters must match exactly in MatchStr$ and MainStr$. |
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Restrictions |
Special search terms are evaluated in this sequence:
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See also |
EXTRACT$, LCASE$, LEFT$, LTRIM$, MID$, RIGHT$, RTRIM$, SHRINK$, TALLY, TRIM$, UCASE$, VERIFY |
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Example |
' x$ = first command-line argument, assuming
spaces, commas, IF INSTR(COMMAND$, ANY " ,." + CHR$(9)) > 0 THEN x$ = "There is more than one command-line argument" ELSE x$ = "There is at most one command-line argument" END IF |