init NSData to nil SWIFT

ios swift nsdata
cmii picture cmii · Dec 3, 2014 · Viewed 22.3k times · Source

How can I init NSData to nil ?

Because later, I need to check if this data is empty before using UIImageJPEGRepresentation.

Something like :

if data == nil {
    data = UIImageJPEGRepresentation(image, 1)
}

I tried data.length == 0 but I don't know why, data.length isn't equal to 0 while I haven't initialized.

Answer

Hector Matos picture Hector Matos · Dec 3, 2014

One thing you can do is ensure your NSData property is an optional. If the NSData object has not been initialized yet, then you can perform your if nil check.

It would look like this:

var data: NSData? = nil
if data == nil {
    data = UIImageJPEGRepresentation(image, 1)
}

Because optionals in Swift are set to nil by default, you don't even need the initial assignment portion! You can simply do this:

var data: NSData? //No need for "= nil" here.
if data == nil {
    data = UIImageJPEGRepresentation(image, 1)
}

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