How to rearange data

[Ofloo]

i wana rearange a string backwards ex: adcb to bcda how would i do this ? without loozing data.

ive checked lsort but it seems that this command hasn't this option..

[spock]

Code: Select all

proc flipstring { s } {
  set newstring ""
  set length [string length $s]
  while { [string length $newstring] != [string length $s] } {
    set newstring "$newstring[string index $s [expr $length - 1]]"
    incr length -1
  }
  return $newstring
}

there are better ways to do this so user, strikelight or ppslim might hit you up

% flip adcb
bcda
% time { flip adcb } 100
1015 microseconds per iteration

maybe some native command does it for you but i assume not since you're asking

[user]

This is about 7 times faster than the above (for short strings) in my tclsh:

Code: Select all

proc reverse str {
	set out ""
	foreach c [split $str ""] {set out $c$out}
	set out
}

[Ofloo]

TnX nice i am amazed that this doesn't give an error ..

set out

???

[user]

set varName ?value?

Returns the value of variable varName. If value is specified, then set the value of varName to value...

[caesar]

As in is the same thing as in using "return" instead of "set" ?

[user]

As in is the same thing as in using "return" instead of "set" ?

Nope...check the 'proc' manual page.

If the procedure doesn't execute an explicit return, then its return value is the value of the last command executed in the procedure's body.

[Ofloo]

ic interesting .. so in a way ur saying if the variable exists , and u set it again then it returns the last executed string or the last string that was set .. basicly its the same as return but not entirely .. so this wouldn't break a loop and still return a value .. example ..

[ppslim]

Yes. This provides a nice way to access variables dynamicly.

IE

Code: Select all

set ourvar "hello"
set thisvar "ourvar"
puts -stdout [set $thisvar]

Mixed with the fact that Proc declarations will return the buffer of the last executed command, if no exclicit return is performed.

This is the precise reason you have to be careful if you are using RAW binds. Because if no return is used, the buffer from the last command is used. Thus.... you can often lose data because you forgot an explicit return.

[caesar]

Heh, nice. Thanks for pointing this out user.