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You’re very close! The statement expression B == 250000 && C == 1 is correct. It returns a value of 1 when the expression is true. That means you have A(1) or A(0). A(1) returns the first row in column A and there are no zero indexes allowed, which is why you get a bad index.
Instead, try wrapping this in an if statement. It will return the first value when true and the second when false.
if(B==1 && C==1, A(#), nan)
The column variable ‘#’ is the way to refer to the row number. Here is an example:
You can also use:
if(B==1 && C==1, A, nan)
This does the same thing but you don’t have to explicitly show the row index.
There is no way to return an empty value using an expression, so instead you use ‘nan’ (not a number). Most of the drawing commands just ignore ‘nan’ values, so you can still graph columns that contain ‘nan’.
If you want to remove the nan values, you can do that with a Mask column. Or you can do the check in one step and use a Mask column to return A based on that column, as shown here.
When you click and drag to zoom into a graph, you can drag the edges of the white bar on the hover controls the change the range. This changes the Restrict in the Axis settings. It sounds like what your running into is the the beginning and end are hard to set to exact values.
You can type in the values you want to get the zoom region to exactly where you want.
Then if you wanted a small range you could set that up and click the center of the bar to pan through the data.
If you need more control, you could set up your own sliders and use variable names in the Restrict settings.
Here a slider is set up to pan through all the data where you control the range as well.
One issue here is that if you accidentially click and drag on the graph, you loose the connection to the varaibles. A solution is to set up the graph and then place in a graph group, so you’re not really working with it. Then include the image using a Graphic command in a different graph. One advantage is that you can include a second inset that shows the entire data set. You also can’t break the connection with the variables as these are like dynamic screen shots.
We created an example file that demonstrates, so you can see the x portion that is zoomed in based on the whole set of data.
You can find this file now when you open File >Online Examples. It is in the Layout section. You should be able to paste your own data over the columns in this file to test it out. Hope this helps and would appreciate any feedback!
For Expression columns, you have to type in the name of the columns in the column object entry box. Here is a simpler example. The first expression is saying ‘First expression = numbers’, and just returns the same values. The second expression is a logical statement using mathematical operators to check when the values in the column are equal to 4. These logical statments return a “1” when true.
Expresssions may break if you move a column into different group or change the name. You also have to use a path name or a redirect column when the column you want to reference is not in the same location as where you are testing the criteria.
Hope that helps.
Hi Richard,
You are correct the Mask column can only do one criterion at a time.
Instead you can create expression that evaluate muliple logical criteria. For example, here is a column created to idenify where first is one and second is two. Then you could mask using the criteria column. If the columns you are comparing to are text columns, you can use the options in the text column object, to map to numbers.
Note rather than using a mask column, you can add muliptle criteria to masks in commands or command groups.
Do either of these approaches solve your issue?