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Michael12345
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What is the meaning of it?
The episode shown in picture_1 was extracted from "Scripting Mikrotik WiKi" about the usage of "find" command. I really want to know what is the exact meaning of the last figure "-1".Minus one? or dash one? I have try to "+3" or "-5", but result seems nothing change.
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Re: What is the meaning of it?
it's 'minus one'. 'find' will look for <arg2> starting at the position (<start> + 1) - not sure why... so,
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[admin@MikroTik] > :put [:find "abc" "a" 0];
[admin@MikroTik] > :put [:find "abc" "a" -1];
0
[admin@MikroTik] >
Last edited by Chupaka on Sat Nov 21, 2009 6:17 pm, edited 1 time in total.
Re: What is the meaning of it?
It's the starting position, the string will be searched beyond that character position. Character positions are 0 based, so in the string "abc" the string "a" appears at position 0. Since the starting positions gives the character positions beyond which the string will be searched,
yields null, since there is no "a" beyond character position 0. You have to search from the very start of the string, which is character position -1 (minus one).
works fine, however, since "b" is beyond character position 0, as it is at character position 1.
Really that's not worth memorizing, since the starting position is an optional parameter that defaults to -1 and searches the entire string. If you do need to start searching further into the string, just remember that positions are given based on 0, most probably because the search simply treats the string as a 0 based array.
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:put [:find "abc" "a" 0];Code: Select all
:put [:find "abc" "b" 0];Really that's not worth memorizing, since the starting position is an optional parameter that defaults to -1 and searches the entire string. If you do need to start searching further into the string, just remember that positions are given based on 0, most probably because the search simply treats the string as a 0 based array.