Iterating over features

Now, it's time to discover how to get all the features or a subset of them. The main way to iterate over all features or records of myVector is by using the following code, which shows the ID of each feature:

for feature in myVector.getFeatures():
    feature.id()

This will print a list of all 653 record IDs, as shown here:

0
1
...[cut]...
652

It's not always necessary to parse all records to get a subset of them. In this case, we have to set the QgsFeatureRequest class parameters to instruct getFeatures and then retrieve only a subset of records; in some cases, we must also retrieve a subset of columns.

The following code will get a subset of features and columns:

rect = QgsRectangle(1223070.695, 2293653.357, 9046974.211,
 4184988.662)
myVector.setSubsetString('"AREA_MI" > 1000')
request = QgsFeatureRequest()
request.setSubsetOfAttributes...