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let players = ["Greg", "Jenn", "Steve", "Anthony", "Krista", "Marti", "Erin", "Brandon",].shuffled()
I want to loop over the array and have it print out all pairs after being shuffled... so if the above was the outcome after being shuffled... it would print out
Greg, Jenn
Steve, Anthony
Krista, Marti
Erin, Brandon
you could use this:
if !players.isEmpty {
let arrTpl = stride(from: 1, to: players.count, by: 2).map { (players[$0-1], players[$0]) }
print("\(arrTpl)")
}
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I want to compute the square of mean-square for each element of l
l=[0.02817088, -0.74100320, -0.54062120, -0.24612808, 0.06945337, -0.58415690, -0.51238549,
-0.07862326, -0.42417337, -0.33482340, -0.21339753, -0.03890844, -0.59325371, 0.28154593,
-0.32133359,-0.13534792, 0.14060645, 0.32204972, 0.44438052, -0.21750973,-0.59107599,
-0.60809913]'
k= -0.2224834
sum(l-k)^2/22
I am not sure if sum(l-k)^2/22 is the sum of each (l[j]-k) for j=1,2,...,22?
ans = 2.4223e-14
I guess what you need might be
>> mean((l-k).^2)
ans = 0.10945
Data (You need ... for line continuation if you have data in different lines for l)
l=[0.02817088, -0.74100320, -0.54062120, -0.24612808, 0.06945337, -0.58415690, -0.51238549, ...
-0.07862326, -0.42417337, -0.33482340, -0.21339753, -0.03890844, -0.59325371, 0.28154593, ...
-0.32133359,-0.13534792, 0.14060645, 0.32204972, 0.44438052, -0.21750973,-0.59107599, ...
-0.60809913]'
k= -0.2224834
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In my while statement, I cannot understand why my output is printed twice ?
I would like to print i only one time, where is my error ?
func fetch2(){
var i: Int = 0
while i <= (self.returned-1) {
let itemLookUp = "https://shopping.yahooapis.jp/ShoppingWebService/V1/json/itemLookup?appid=\(self.appId)&itemcode=\(self.arrayCodeProduct[i])&responsegroup=large"
print(i)
i = i+1
}
}
Here is the output that I obtain :
0
1
2
3
0
1
2
3
Thank you in advance.
It looks like fetch2() is called twice.
Add a print(#function) before you var i and check that fetch2() is not called several times.
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Let's say you have an Int.
let int = 12345
I want it to only display some of the digits.
For example: print(firstTwoDigits) --> 12
How do I do this and thank you in advance.
It depends on your specific requirements.
This prints the first two digits of an integer number
let intVal = 12345
print(String(intVal).prefix(2))
Output: 12
Another way which only prints certain ones in the number:
let intVal = 12345
let acceptableValues = ["1", "2"]
let result = String(intVal).filter {
acceptableValues.contains(String($0))
}
print(result)
Output: 12
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How can I create key/value-array pair in Scala. By this I mean in place of value I need an array.
val newRdd1 = rdd1.flatMap(x=>x.split(" "))
.map({case (key, Array(String)) => Array(String) })
You can achieve it using map(), it is similar in either plain scala program or Scala-in-SparkContext.
Example, you have a list of strings:
var sRec = List("key1,a1,a2,a3", "key2,b1,b2,b3", "key3,c1,c2,c3")
You can split it & convert to key/value(array of strings) assuming key is in 0th position, using:
sRec.map(x => (x.split(",")(0), Array(x.split(",")(1), x.split(",")(2), x.split(",")(3)))).
foreach(println)
(key1,[Ljava.lang.String;#7a81197d)
(key2,[Ljava.lang.String;#5ca881b5)
(key3,[Ljava.lang.String;#24d46ca6)
If you want to read a particular array element by key:
sRec.map(x => (x.split(",")(0),Array(x.split(",")(1), x.split(",")(2), x.split(",")(3)))).
map(x => (x._1, x._2(0))).foreach(println)
Output:
(key1,a1)
(key2,b1)
(key3,c1)
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Assuming I have the following Scala classes:
Human(id: String, task: Task)
Task(id: String, time: Duration)
And having a List[(Human, Task)] with the following elements:
("H2", Task("T3", 5 minute))
("H3", Task("T1", 10 minute))
("H1", Task("T1", 10 minute))
("H1", Task("T2", 5 minute))
Now I want to functionally check if close elements have the same duration, and if so, order them by the human id.
In this case, the final list would have the elements sorted like so:
("H2", Task("T3", 5 minute))
("H1", Task("T1", 10 minute))
("H3", Task("T1", 10 minute))
("H1", Task("T2", 5 minute))
I tried to use sortBy to do so, but the way I'm doing, the final list will be fully ordered by the Human ID, not comparing the times.
Does anyone have any idea how can I do this?
Your question is a bit confused. You say you have a List of (Human,Task) tuples, but then you describe a collection of (String,Task) tuples.
Here's a way to sort a List[Human] according to the rules you've described.
def sortHumans(hs: List[Human]): List[Human] =
if (hs.isEmpty) Nil
else {
val target = hs.head.task.time
hs.takeWhile(_.task.time == target).sortBy(_.id) ++
sortHumans(hs.dropWhile(_.task.time == target))
}