< iOS 11 below code works to hide the tableView Section Height for the first section.
self.tableView.estimatedSectionHeaderHeight = 20.0
self.tableView.contentInset = UIEdgeInsetsMake(-18.0, 0.0, 0.0, 0.0)
For iOS 11 what should works?
I tried setting section 0 to 'nil' from titleForHeaderInSection
and heightForHeaderInSection to '0' for first section but it didn't work.
self.tableView.tableHeaderView = UIView(frame: CGRect(x: 0, y: 0, width: self.view.frame.size.width, height: 0.01))
try this – Kamal Upasena