add leading zeros

KNIME Analytics Platform
1

Hi,

I'm looking for a simple way to add leading zeros to integers in a column that range from 1 to n (where n is less than 1000) before then concatenating with a two characters sting (using the join function in the string manipulation node), so that the resulting string is always 6 characters long.

Does anyone know of a simple way of doing this?

Cheers,

Andy

2

This can be done easily with the R integration and the formatC function..  

http://stat.ethz.ch/R-manual/R-devel/library/base/html/formatc.html

 

In an R snippet (KNIME2.10+, or with the Labs integration in previous versions), you could add something like:

newcol = formatC(knime.in$"index",width=6, format="d", flag="0")

knime.out <- cbind(knime.in, newcol)

3

Hi Aaron,

Sounds ideal.

I'm in 2.9 as have yet to test all processes still work in 2.10.

I'll download the nodes & have a look at the R snippet and try your suggested code.

Cheers,

Andy 

 

4

Hello Andy,

For a solution that works for any version of KNIME, you could use a Java Snippet (simple):

return $myString$+String.format("%04d", $myInt$);

Given this table:

myString myInt
df 1
ry 1
gh 10
fg 100
bv 0
hg 789
uy 423
rt ?

here is the output:

myString myInt new column
df 1 df0001
ry 1 ry0001
gh 10 gh0010
fg 100 fg0100
bv 0 bv0000
hg 789 hg0789
uy 423 uy0423
rt ? ?

Note that a value of 0 is ok but that a null will null the output. Also, negative values will have the minus squeezed between your two characters and the padded integer.

HTH,

Fred

5

Hi Aaron,

I have a problem with the solution, when I try and run the R snippet I get the following errors,

either;

the node hangs and I can't cancel it - and I get a message "Strange state CONFIGURED encountered in cancelExecution()"

the node hangs and I can cancel it - and i get the message "Execute failed: Failed to convert table node inputs into r workspace variables: org.knime.core.node.CanceledExecutionException: ProgressMonitor has been canceled."

or I can't execute at all - and I get the message "Execute failed: voidEval failed, request status: error code: 127"

I have R 3.0.3 installed, and had to install the RServe package and start Rserve using the Knime prompted command; library(Rserve); Rserve(args = "--vanilla").

I'm using the Knime Labs R snippet node.  In the R Snippet node I've kept the code the same excepting two changes, to the variable name I'm using (temp) and the length (4).

  newcol = formatC(knime.in$"temp",width=4, format="d", flag="0")

  knime.out <- cbind(knime.in, newcol)

any help resolving would be much appreciated...

Cheers,

Andy

6

Hi Frederic,

That worked a treat, thank you very much!

I guess I'll leave R integration for another day, though with the way things are, it won't be long!

Cheers,

Andy

 

7

Thanks for the tip Frederic.  Andy, if you update to 2.10 and still have problems with it, post in the R section and I'll take a look at it in more details. 

Best,

Aaron