在Swift中使用NSDateFormatter时我得到零

Question

This is my code :

println(myStringDate)    // 2015-02-26T17:46:34.000Z
let dateFormatter = NSDateFormatter()
dateFormatter.dateFormat = "YYYY-MM-DDTHH:mm:ss.sssZ"
let myDate = dateFormatter.dateFromString(myStringDate)
println(myDate)        // nil

Why nil ? What am I doing wrong ?

Answer 1

Your problem is how you set the date format. Because there is a T in your string, you need to "escape" it and say, that it shouldn't affect the formatting of the date.

dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSSZ"

Also as you see, I've changed the sss to SSS which stands for miliseconds and also changed the year YYYY to lowercase yyyy also the same with the DD . You have to be really carefully, when to use upper and lowercase letters in your Dateformat-strings.

Check @HotLicks link in the comments which shows a great overview of the dateformat usage.

Answer 2

I know that it's to late, but

dateFormatter.dateFormat = "YYYY-MM-DD'T'HH:mm:ss.sss'Z'"

should be

dateFormatter.dateFormat = "YYYY-MM-DD'T'HH:mm:ss.SSS'Z'"

because,

1)

ss - seconds
SSS - fractional second

sss != SSS

2)

  T -> 'T'; S -> 'S'

And nice tutorial