Remove n number of characters from the end of the strings in a column

I read someone had difficulties with this function.
Now I am trying to figure out the same thing and I have a suggestion on that:
We currently have String Manipulation (node) > removeChars(str, chars) (function), and some combo of length and substring.
I think it would be great to have removeNChars added as follows:

  1. removeNChars(str, n)
    or for better interpretation
  2. removeNChars(str, start/end, n)
    where str is the string to manipulate and
    n is the number of symbols to remove (trim).
    In 1. n>0 would mean “remove n chars from start”; n<0 would mean “remove n chars from end”
    in 2. n could follow the current logic (<0 defaults to 0) and start/end would mark from which position the counter should start counting.

I’d appreciate thoughts on this.

Hi,

In the Column expressions node in the latest version was added the function right() (and also left()) and they behave like in excel … extracts the rightmost (leftmost) characters of a string.

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Sorry, but I can’t find such a node, nor these functions in the String Manipulation node. My version is 4.2.3.

Hi,

The node is part of the KNIME labs group

Maybe you have not installed it … look at Community extensions … https://www.knime.com/community

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Just to make it clear and to avoid future reader’s confusion, I found what you talk about here:
image
and somehow it does install in the group: KNIME Labs in the Node Repository
All clear, thanks!

But… oh, gosh, if I have to go through this node!
My suggestion still holds.

Hello @deicide_bg,

don’t think there is a need for such function as substring() function seems pretty straightforward:

  • substr($col_name$, n) :arrow_right: removes first n chars from string
  • substr($col_name$, 0, length($col_name$) - n ) :arrow_right: removes last n chars from string

Hope this helps!

Br,
Ivan

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You may be right. I went down a bit different path of thought, the one that goes to a left/right (excel-like) function. Thanks for the response!

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