How do I switch UISegmentedControl programmatically?

Alternatively, after you have changed the selectedSegmentIndex call 'sendActionsForControlEvents:' for example

segmentedControl.selectedSegmentIndex = 0

[segmentedControl sendActionsForControlEvents:UIControlEventValueChanged];

SWIFT 5:

segmentedControl.selectedSegmentIndex = 0
segmentedControl.sendActions(for: .valueChanged)