Replace column values using Apache NiFi

Question

I have a sample csv looks like this

ID,FNAME,PROBLEM_COL
1,sachith,
2,nalaka,
3,john,
4,adams,

Always PROBLEM_COL value is empty. I want to replace empty with null string.

For that I used UpdateRecord processor and CSVReader with Use String Fields From Headers
Custom value as /PROBLEM_COL and ${field.value:replaceFirst('','null')}

This runs without error/warning. But PROBLEM_COL is not replaced. I had referred this, but this does not solve my issue. My headers are in block-letters.

score 1 · Answer 1 · answered Dec 01 '21 at 12:18

1

try to change your regex to be something like

',$'

which means: comma followed by end of line

answered Dec 01 '21 at 12:18

YuriR

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score 1 · Accepted Answer · answered Dec 01 '21 at 12:44

1

Use replaceEmpty('null') instead of replaceFirst

https://nifi.apache.org/docs/nifi-docs/html/expression-language-guide.html#replaceempty

answered Dec 01 '21 at 12:44

daggett

26,404
3
40
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score 1 · Answer 3 · answered Dec 03 '21 at 11:07

1

With processor UpdateRecord you can use

replace( /PROBLEM_COL, '', 'null' )

answered Dec 03 '21 at 11:07

Dario Lurido

98
7

Replace column values using Apache NiFi

3 Answers3