MichiZH questions

• R: Set a value for certain data meeting two conditions
• iOS: Check if coredata object still exists?
• R: xts get year or month for a certain row in a xts time series object
• Print multiple lines without printing the print()
• iOS: Collection view, selectItemAtIndexPath programmatically doesn't work
• iOS 8: Cannot change the navigation bar at all of the ABPeoplePickerNavigationController
• Change plot area background color
• CoreData: How to correctly use migratePersistentStore to create a backup copy
• iOS CoreData: How to setup the core data "connection"? Stanford UIDocument vs. Apple template?
• Firebase Crashlytics: Missing dsym files

MichiZH answers