get last occured string

[snowingnow]

That says, we have "A^cur~B1^pre~B2^pre~C^lat"
since "B1^pre~B2^pre" of pre componet could repeat more than two time, i only need to get the last one for pre component
than the result come as ""A^cur~B2^pre~C^lat", how can i do that, thanks

 

[Bong]

It's not clear to me what you're asking. You have an input string, A, and you want to delete all but one (consecutive?) instance of a substring, B, from that string?

_________________
Bob Rashkin

 

[snowingnow]

Yes, sorry for the confusion, i want to keep only the last one of substring B

 

[Bong]

Let's say the bigger string is string_a. Further, let the repeating substring, that you only want one of, is string_b. Now, assuming that the only occurrence of string_b is the consecutive recurrence somewhere in string_a but not multiple non-recurring instances:

set i1 [string first $string_b $string_a]
set i2 [string last $string_b $string_a]
incr i2 -1
set string_a [string replace $string_a $i1 $i2]

_________________
Bob Rashkin