If Statement in Column Expressions

[dibu]

Hi, I would need a code in column expressions which returns a double value from the column price in an appended column “price-new” if the column “status” contains the string “L_*” . Is there a solution? Thank you in advance…

[dibu]

…the Asterisks Sign is a Joker for a string. Maybe it works with a Java-Snippet…

[mehrdad_bgh]

Hi @dibu

if (regexMatcher(column(“column1”),“L_\*.+”)){
toDouble(column(“column2”))
}

Change the names of columns. You can use “Else” to manage missing value of new column
GL

[dibu]

Hi mehrdad_bgh, thank you. I tried that in column expression and got the following Error-Message (Expected an Operand…)

Errors in code. Please fix the expression.
Expected an operand but found error

if (regexMatcher(column(“combined_string”),“L_*.+”)){

                                       ^ at line 1 at column 44

[mehrdad_bgh]

Hello @dibu

Can you upload your workflow here?

[armingrudd]

Hi @dibu,

I think the expression provided by @mehrdad_bgh has two back slashes (\\) originally, not a single one.

So the expression actually is:

if (regexMatcher(column("column1"),"L_\\*.+")){
toDouble(column("column2"))
}

@mehrdad_bgh, when you want to share some code, you need to provide it as a preformatted text. If it’s a single line code, select the line and click on the “</>” icon or add a single back quote at the beginning and the end of the line:

`your code`

If it’s multi-line, add a triple back quote line at the beginning and the end like this:

```
Your code here
Second line here
```

[dibu]

KNIME_Example.xlsx (17.7 KB)

…here is my Example, the result should be column G. Thank you in advance!

[mehrdad_bgh]

Hi @armingrudd

I didn’t know that. Thank you for your information. But actually my code had one backslash() and I used two backslashes for sharing the code.

[dibu]

@armingrudd, thank you, here it delivers the error- message: NullPointerExeption.

[mehrdad_bgh]

Hi @dibu

 if (regexMatcher(column("Status"),"L_*")){
    column("Price")
}

GL

[armingrudd]

So you have missing values in the status column. Use this expression instead:

if (isMissing(column("status"))) null
else if (regexMatcher(column("status"),"L_\\*.*")) toDouble(column("price"))

[dibu]

@mehrdad_bgh; @armingrudd; thank you both! All of your Solutions are working. The KNIME Community is simply great!