Conditional Binding if let error Initializer for conditional binding must have Optional type

Question

I am trying to delete a row from my Data Source and the following line of code   if let tv   tableView     causes the following error      Initializer for conditional binding must have Optional type  not   UITableView   Here is the full code      Override to support editing the table view  func tableView tableView  UITableView  commitEditingStyle editingStyle UITableViewCellEditingStyle  forRowAtIndexPath indexPath  NSIndexPath        if editingStyle     Delete               Delete the row from the data source      if let tv   tableView                myData removeAtIndex indexPath row               tv deleteRowsAtIndexPaths  indexPath   withRowAnimation   Fade    How should I correct the following    if let tv   tableView

User · Answer

Well  it d still be convenient  syntactically  if we could declare usual values inside the if s condition  So  here s a trick  you can make the compiler think there is an assignment of Optional some T  to a value like so      if let i    quot abc quot  firstIndex of   quot a quot            let i int    some i utf16Offset in   quot abc quot             i int  lt  1              Code

User · Answer

if let if var optional binding only works when the result of the right side of the expression is an optional   If the result of the right side is not an optional  you can not use this optional binding   The point of this optional binding is to check for nil and only use the variable if it s non-nil   In your case  the tableView parameter is declared as the non-optional type UITableView   It is guaranteed to never be nil   So optional binding here is unnecessary   func tableView tableView  UITableView  commitEditingStyle editingStyle UITableViewCellEditingStyle  forRowAtIndexPath indexPath  NSIndexPath        if editingStyle     Delete              Delete the row from the data source         myData removeAtIndex indexPath row          tableView deleteRowsAtIndexPaths  indexPath   withRowAnimation   Fade    All we have to do is get rid of the if let and change any occurrences of tv within it to just tableView

User · Answer

condition binding must have optinal type which mean that you can only bind optional values in if let statement   func tableView   tableView  UITableView  commit editingStyle  UITableViewCellEditingStyle  forRowAt indexPath  IndexPath         if editingStyle     delete               Delete the row from the data source          if let tv   tableView as UITableView                          This will work fine but make sure when you use if let it must have optinal type

User · Answer

for my specific problem I had to replace  if let count   1                  do something             With   let count   1 if count  gt  0                   do something

User · Answer

What it is telling you is - the 2nd guard let or the if let check is not happening on an Optional Int or Optional String  You already have a non-optional value  so guarding or if-letting is not needed anymore

User · Answer

In a case where you are using a custom cell type  say ArticleCell  you might get an error that says        Initializer for conditional binding must have Optional type  not  ArticleCell    You will get this error if your line of code looks something like this       if let cell   tableView dequeReusableCell withIdentifier   ArticleCell  for indexPath  indexPath  as  ArticleCell    You can fix this error by doing the following        if let cell   tableView dequeReusableCell withIdentifier   ArticleCell  for indexPath  indexPath  as ArticleCell    If you check the above  you will see that the latter is using optional casting for a cell of type ArticleCell

User · Answer

Same applies for guard statements  The same error message lead me to this post and answer  thanks  nhgrif    The code  Print the last name of the person only if the middle name is less than four characters    func greetByMiddleName name   first  String  middle  String   last  String          guard let Name   name last where name middle  characters count  lt  4 else           print  Hi there            return           print  Hey   Name         Until I declared last as an optional parameter I was seeing the same error

[ios] Conditional Binding: if let error – Initializer for conditional binding must have Optional type

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