Contents
What are the functions in the QGIS field calculator?
QGIS FIELD CALCULATOR. This group contains operators (e.g., +, -, *). This group contains functions to handle conditional checks in expressions. This group contains math functions (e.g., square root, sin and cos).
How do I update a field in field calculator?
In the field calculator dialog, you first must select whether you want to only update selected features, create a new attribute field where the results of the calculation will be added or update an existing field.
Where do I find the function list in QGIS?
The Function List contains functions as well as fields and values. View the help function in the Selected Function Help. In Expression you see the calculation expressions you create with the Function List. For the most commonly used operators, see Operators.
Where are the conversions group functions in QGIS?
The Conversions group contains functions that convert one data type to another. The String group provides functions for data strings. In the Geometry group, you find functions for geometry objects. With Record group functions, you can add a numeration to your data set.
How to create conditional statement in QGIS field calculator?
I just tested this : You can use the condition several times: WHEN cat = 1 THEN 205 WHEN cat = 2 THEN 215 WHEN cat = 3 THEN 225 WHEN cat = 4 THEN 235 …. Something like this perhaps: Highly active question. Earn 10 reputation (not counting the association bonus) in order to answer this question.
How to create a virtual field in QGIS?
You can also create a virtual field, which will automatically return an updated value in case the values in cat change (e.g. you edit the layer). Remember that the values of virtual fields will not be saved in the dataset and are only visible inside this QGIS project. I just tested this : You can use the condition several times:
How to fill a column in a field calculator?
I’d be thankful for a code example for the field calculator (including the use of $rownum (I think I need this for switching to the line)). Just put $rownum (QGIS 2) or @row_number (QGIS 3+) as the expression. Simple as that.