CODEWITHSUNDEEP
swiftswift3nsdateformatter
SpaceX
SpaceX

Reputation: 2890

How to convert an array of date strings to an array of date objects, Swift

Looked at similar SO questions and found that there are no answers in Swift, there are plenty of answers exclusively for date formatting but not in combination with iteration.

I have an array of date strings like the below:

let dateStrings = ["2016-12-22T08:00:00-08:00", "2016-12-22T08:15:00-08:00", "2016-12-22T08:30:00-08:00"]

I would like to convert them to an array of local dateObjects like the below

var dateObjects = [2016-12-22 21:30:00 +0530, 2016-12-22 21:45:00 +0530, 2016-12-22 22:00:00 +0530]

I've tried iterating through the array of date strings but I get this error :

"fatal error: unexpectedly found nil while unwrapping an Optional value"

So I tried with optional binding without success. Please advice where I could be going wrong.

var dateObjects = [Date]()
let dateFormatter = DateFormatter()
for date in dateStrings{
    dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ssZZZZZ"
    let dateObject = dateFormatter.date(from: date)
    self.dateObjects.append(dateObject!)  // ERROR LINE
}

When I try with optional binding its going through else statement printing "Unable to convert to date object" 

for date in dateStrings{
    dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ssZZZZZ"
    if let dateObject = dateFormatter.date(from: date){
        self.dateObjects.append(dateObject!)  // ERROR LINE
    }
    else{
        print("Unable to convert to date object")
    }
}

Upvotes: 0

Views: 5353

Answers (5)

Christian Heath
Christian Heath

Reputation: 221

What I did was that I mapped over the the array and made each item into a new Date object. 

let dateObjects = _.map(dateStrings, (dateString) => new Date(dateString)

It's that easy. In my case, I was trying to compare the dates to another array of dates so after doing new Date(dateString) I converted them back into a ISOString by doing 

let dateObjects = _.map(dateStrings, (dateString) => new Date(dateString).toISOString()

Note:
You don't need to use _.map, you could just use .map

Upvotes: 1

Kunal Verma
Kunal Verma

Reputation: 602

Try This..

Swift 3

let dateStrings = ["2016-12-22T08:00:00-08:00", "2016-12-22T08:15:00-08:00", "2016-12-22T08:30:00-08:00"]

func convertDate(str: String) -> Date {
    let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ssxxx"
        let dateObject = dateFormatter.date(from: str)
    return(dateObject!)
}

var stringDates : [Date] = []

for date in dateStrings {
    stringDates.append(convertDate(str: dateStrings[0]))
}

Upvotes: 0

Museer Ahamad Ansari
Museer Ahamad Ansari

Reputation: 5523

Try this: date object is local variable so remove self. if you want use self then make it global 

    let dateStrings = ["2016-12-22T08:00:00-08:00", "2016-12-22T08:15:00-08:00", "2016-12-22T08:30:00-08:00"]

    var dateObjects = [Date]()
    let dateFormatter = DateFormatter()
    dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ssZZZZZ"

    for date in dateStrings{
        let dateObject = dateFormatter.date(from: date)
        dateObjects.append(dateObject!) 
    }

    print(dateObjects)

Upvotes: 2

Sahil
Sahil

Reputation: 9226

Simply remove self from dateObjects.

dateObjects is local variable. So don't use self with dateObjects.

var dateObjects = [Date]()
let dateFormatter = DateFormatter()
for date in dateStrings{
    dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ssZZZZZ"
    let dateObject = dateFormatter.date(from: date)
   dateObjects.append(dateObject!)  
 }

Upvotes: 1

Nirav D
Nirav D

Reputation: 72410

In second case you are force wrapping non-optional value there is no need of that and you are writing self with dateObjects var that is not declare as a instance property, also you can simply use flatMap to reduce your code and create array of Date from array of String.

let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ssZ"
let dateObjects = dateStrings.flatMap { dateFormatter.date(from: $0) }

Upvotes: 7

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