With this option s selection of values can be transformed using a regular expression (see figure 1).
figure 1: Apply Transformation window
By selecting the 'Only apply to missing data' checkbox, the transformation will only be performed for the selected fields that do not already contain a value.
A regular expression can be composed using the following elements:
VARIABLES
The variables that can be used to compose an expression are the alphabetical indexes of columns. These can be found in the coloured area of the column headers (see figure 2) and are case sensitive.
figure 2: Alphabetical column indices
OPERATORS
operator |
description |
example |
---|---|---|
+ |
add |
A+3 |
- |
subtract |
B-C |
* |
multiply |
A*0.5 |
/ |
divide |
B/A |
^ |
power |
A^2 |
FUNCTIONS
function |
description |
example |
---|---|---|
sum |
sum of values |
sum(A,B,...) |
abs |
absolute value |
abs(A) |
pow |
power function |
pow(A,2) |
sqrt |
square root |
sqrt(B) |
min |
minimum of list |
min(A,B,C) |
max |
maximum of list |
max(A,B,C) |
average |
average of list |
average(A,B,C) |
exp |
exponential (e^x) |
exp(A) |
ln |
natural logarithm |
ln(A) |
log |
logarithm base 10 |
log(A) |
atanh |
inverse hyperbolic tangent |
atanh(A) |
acosh |
inverse hyperbolic cosine |
acosh(A) |
asinh |
inverse hyperbolic sine |
asinh(A) |
tanh |
hyperbolic tangent |
tanh(A) |
cosh |
hyperbolic cosine |
cosh(A) |
sinh |
hyperbolic sine |
sinh(A) |
atan |
arc tangent |
atan(A) |
acos |
arc cosine |
acos(A) |
asin |
arc sine |
asine(A) |
tan |
tangent |
tan(A) |
cos |
cosine |
cos(A) |
sin |
sine |
sin(A) |
if |
logical expression |
if(evaluation,expression1,expression2) |
isMissing |
check for NaN |
isMissing(A) |