This node provides the possibility to append an
arbitrary number of
flow variables or modify existing variables using expressions.
For
each variable
that shall be appended or modified a separate expression
is defined.
These expressions can be simply created using predefined
functions
similar to
the
Math Formula
and
String Manipulation
Nodes). Nevertheless there is no restriction on the number of lines
an expression has and the number of functions it uses. This allows
users to create their own complex expressions.
Additionally, intermediate results of functions or calculations can
be stored
within an expression by assigning them to variables
(using
'=').
This allows that these
results can be reused in different parts
of the expression
after they
have been assigned (see Examples).
Note:
the names of these variables must be different to all of the
predefined function identifiers. Otherwise an error will occur.
To change an expression of an output variable it has to
be
selected in the list of expressions. By selecting an expression the
Expression Editor shows up and the user can modify the expression in
the provided text area.
Available flow variables
can
be
accessed
via
the provided method
variable("varName").
For
each expression
the last
computed instruction
will
be returned.
The syntax and grammar of the expressions are based on the
Javascript
Languange
.
Examples:
-
5*7+3
will append a variable with the value 38.
-
v = variable("knime.workspace")
substr(v, lastIndexOfChar(v,"/"), length(v))
will create a variable containing the folder name of the KNIME workspace folder.
-
"a1"
"a2"
will create a variable with the value "a2", whereas
a1 = "a1"
a2 = "a2"
a1
will create a variable with the value "a1".
Options
General
Expression Table
Expression Editor
Popular Predecessors
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Workflows
00_xplan sf dbconv-insert via xport-AccountKNIME Hub
00. Install ExtensionsKNIME Hub- 00. Install ExtensionsKNIME Hub
- 00. Install ExtensionsKNIME Hub
- 00. Install ExtensionsKNIME Hub
- Show all 490 workflows
Links
- String Flow Variable and Rule Engineby armingrudd on 2019-04-22forum.knime.com/p/59138
- Formatting date/time from variableby knimediger on 2020-11-09forum.knime.com/p/107650
- Variable Expression: How to use declared variables in expression of the same nodeby elsamuel on 2021-08-19forum.knime.com/p/132351
- if then else with multiple conditionsby izaychik63 on 2021-09-17forum.knime.com/p/134816
- Define multiple input variables in one nodeby izaychik63 on 2020-01-29forum.knime.com/p/80149
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