Convert negative values to positive and positive to negative

KNIME Analytics Platform
4

Hi @tdewagner & welcome to the KNIME community

I guess the difficulty here comes from the list of proposed functions in the -Math Formula- node which does not include the basic mathematical operators “+,-,*,/”.

The -Math Formula- node allows writing a mathematical formula as a combination of functions and basic mathematical operations. Parenthesis “(,)” to prioritize operations are also allowed. As explained in the help, one can also deal with NaN values (or missing values) with the following operators:

NaN values act as value true in boolean expressions and
compared to anything (including NaN)
in any way (including ==, but not !=,
which is like !(... == ...)) is false (0).

Moreover, there is an “if-then-else” condition which allows writing conditional mathematical operations, for instance:

if( $value$ >=0, $value$, 0)

Here the formula is for instance setting to zero any negative value. Another example here:

In the precise case of needing to change the sign of a number, @Thyme’s solution is definitely the most appropriate.

Hope all these explanations help.

Best

Ael

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