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darton
Op
Joined: 21 Jan 2006
Posts: 155
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 Posted: Sat Jun 24, 2006 5:45 pm Post subject: Problem with decreasing a variable |
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Hello!
In one of my scripts there is this line:
| Code: | | incr i [lindex $line 0] |
But now I don't want to increase it but I want to decrease it. So I changed it to this:
| Code: | | incr i [lindex $line 0] -1 |
It does not work. The error is: Tcl error [flag]: wrong # args: should be "incr varName ?increment?"
What's wrong? |
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Garp
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Joined: 15 Sep 2003
Posts: 29
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| Posted: Sat Jun 24, 2006 9:17 pm Post subject: Re: Problem with decreasing a variable |
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| darton wrote: | | Code: | | incr i [lindex $line 0] -1 |
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you do something like "1 +1 -1" but incr allows only one operation like "1+1" or "1-1"
(($i + $y) - $z) it would be something like
| Code: | | set i [expr [incr i [lindex $line 0]] -1] |
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DragnLord
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Joined: 24 Jan 2004
Posts: 711
Location: C'ville, Virginia, USA
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| Posted: Sat Jun 24, 2006 11:15 pm Post subject: |
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simply:
in the script you have '[lindex $line 0]' is used to obtain the increment value |
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darton
Op
Joined: 21 Jan 2006
Posts: 155
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| Posted: Sun Jun 25, 2006 6:15 am Post subject: |
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| With the '[lindex $line 0]' it is defined what should be increased. So none of your scripts work. |
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Sir_Fz
Revered One
Joined: 27 Apr 2003
Posts: 3793
Location: Lebanon
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| Posted: Sun Jun 25, 2006 7:40 am Post subject: |
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| Code: | | incr i -[lindex $line 0] |
this will decrement i by '[lindex $line 0]' instead of increment.
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darton
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Joined: 21 Jan 2006
Posts: 155
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| Posted: Sun Jun 25, 2006 9:09 am Post subject: |
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| Yes, it works Sir_Fz. But if i is 3 and it should be decreased the result is 2. With your script it is not 2, but -2. With "trimleft" I can make the variable i positive again, but maybe this is too circumstantial and there is an easier way. |
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DragnLord
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Joined: 24 Jan 2004
Posts: 711
Location: C'ville, Virginia, USA
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| Posted: Sun Jun 25, 2006 9:43 am Post subject: |
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if is "2"
| Code: | | incr i -[lindex $line 0] |
means that it is increased by -2, which means it is decreased by 2
obviously you didn't bother to try it[/code] |
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phab
Voice
Joined: 22 Aug 2005
Posts: 12
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| Posted: Mon Jun 26, 2006 5:59 pm Post subject: |
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Doenst | Code: | | set i [expr {$i - [lindex $line 0]}] |
work? |
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De Kus
Revered One
Joined: 15 Dec 2002
Posts: 1361
Location: Germany
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| Posted: Tue Jun 27, 2006 3:35 am Post subject: |
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its equivalent with 'incr i -[lindex $line 0]', however only the expr one will work on negative values.
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