Question about Select by Attribute and Field Calculator

[EGardner7]

When I first select by attribute and then use python in field calculator am I only editing the fields for the attributes I selected for or is it still editing everything? Thanks!

[PTW]

After selecting by attribute, right click the layer and go to Selection -> Make Layer from Selected Features. This will create a temporary layer and you may want to right click and go to Data-> Export Features and you can save the subset layer. Then use the new saved layer and you will only edit the desired fields.

[EGardner7]

So that means when I have the show selected records button pressed and then I enter something into field calculator it will still edit things that aren't selected? 

[BlakeTerhune]

After making a selection, you can use the CalculateField Python command (or geoprocessing tool) to edit the fields of only the selected records. However, make sure your input for it is the layer with the selection and not a generic path to the feature class in the geodatabase. In the latter case, it won't have a selection and it will field calc all records.

You can also run the tool with an undo option in case there is unexpected behavior.

[PTW]

@BlakeTerhunewas more thorough with their response!

The solution I suggested above should guarantee only the desired fields will be updated.

[JimCousins]

The field calculator will only apply to the selected records.

If you are at all concerned, run your field calculations in an edit session, where you have the option to "undo".