I have an array myarray and I am using a for loop to get a few information which I add to myarray. But next time the for-loop runs, I don't want to create a separate index, but instead the 2nd time and so on, I want to append the information to myarray[0].
How do I do that?
var myarray = [String]()
for var j in 0 < 12 {
// do some stuff
for var i in 0 ..< 10 {
let parta = json?["users"][j]["name"].string
let partb = json?["users"][j]["Lname"].string
let partc = json?["users"][j]["dob"].string
myarray.append("\(parta)-\(partb)-\(partc)---")
// Here when the for loop comes back again (i = 1) , i dont want to make
// myarray[1] , but instead i want myarray[0] ,
// having value like [parta-partb-partc--parta-partb-partc]
}
}
Basically what I am trying to do is, append the new name/lname/dob values at myarray[0] without affecting the current value/string at myarray[0].
You can insert single element and also add array as below.
Swift 5
var myarray = [String]()
myarray.insert("NewElement", at: 0)
myarray.insert(contentsOf: ["First", "Second", "Third"], at: 0)
If I understand your question correctly, you want to create one long string and add the new data always at the beginning of the string. One way to do that would be:
// Store somewhere
var myString = String()
for var i in(0..<10) {
let parta = json?["name"].string
let partb = json?["Lname"].string
let partc = json?["dob"].string
let newString = "\(parta)-\(partb)-\(partc)---")
newString.append(myString)
myString = newString
// Here when the for loop comes back again (i = 1) , i dont want to make
//myarray[1] , but instead i want myarray[0] ,
//having value like [parta-partb-partc--parta-partb-partc]
}
Related
I just want to create a dictionary with the help of for loop
sample code :
var counter: Int = 1;
var pageCountDict = [String:Any]();
for filterCount in counter..<6
{
if let count = "page_\(filterCount)_vtime" as? String
{
pageCountDict = [count: timeInterval_Int];
}
}
print(pageCountDict);
This print command give me only last value of forloop
I just want all the value of this variable pageCountDict in a dictonary
The way to assign to a dictionary is first use the subscript and assign the value to it:
pageCountDict[YourKey] = YourValue
Also, you can see many examples and explanations in Apple documentation regarding dictionaries.
With each loop, you are replacing the dictionary with one that contains only one element. What you want to do is this :
pageCountDict[count] = timeInterval_Int
Also, you shouldn't need the as? String part. This should be sufficient :
for filterCount in counter..<6
{
pageCountDict[count] = "page_\(filterCount)_vtime"
}
var pageCountDict = [String:Any]()
You can add values to this dictionary by merging previous contents and new data as follows...
let counter: Int = 1
var pageCountDict = [String:Any]()
for filterCount in counter..<6
{
let value = 9
let count = "page_\(filterCount)_vtime" //'if' is not needed as it is always true
pageCountDict.merge([count: timeInterval_Int], uniquingKeysWith:{ (key, value) -> Any in
//assign value for similar key
timeInterval_Int
})
}
print(pageCountDict)`
Here is my code so far
var counter = 0
for i in 0...9 {
var val = NamePicker()
// array to find duplicates
var buttonValues = ["", "", "", "", "", "", "", "", "", ""] // array for button names
buttonValues.insert(val, at: counter)
print(buttonValues[counter])
counter += 1
}
This code is putting 10 string values into my array. What I would like to do is find a way to check each value in my array. for eample if my end result array is ["a","a","a","b","b","c","c","e","f","c"] I want to see if there is a triple of the same name(single and duplicates are fine). However if there is a triple I would like to change the 3rd value to another val from my NamePicker() function.
so with my array of
["a","a","a","b","b","c","c","e","f","c"]
there are 3 "a" and 3 "c", having two of the same is ok, i would like to change the 3rd to a new values and if the new value makes another triple it will change until there are no more triples.
so that array could possible have an end result of
["a","a","f","b","b","c","c","e","f","z"]
this is where the triples where changed.
Any help on how to do this efficiently?
Both options below asume that your NamePciker() function can generate at least 5 distinct values so there exists an array that satisfies your requirement.
Your requirement is better handled by not generating so many duplicates to begin with. If all you want is an array of names when each name cannot be repeated more than twice, try this:
var buttonValues = [String]()
var dict = [String: Int]()
while buttonValues.count < 10 {
let name = NamePicker()
let count = dict[name] ?? 0
guard count < 2 else { continue }
buttonValues.append(name)
dict[name] = count + 1
}
If you already have the array and want to correct it, do this:
var buttonValues = ["a","a","a","b","b","c","c","e","f","c"]
// Scan the array to tally how many times each name appears
var totalDict = [String: Int]()
buttonValues.forEach { totalDict[$0] = (totalDict[$0] ?? 0) + 1 }
// Now scan it again to update names that appear too many times
var runningDict = [String: Int]()
for (index, value) in buttonValues.enumerated() {
let count = runningDict[value] ?? 0
if count >= 2 {
while true {
let newValue = NamePicker()
let newTotal = (totalDict[newValue] ?? 0) + 1
if newTotal < 3 {
buttonValues[index] = newValue
totalDict[newValue] = newTotal
break
}
}
} else {
runningDict[value] = count + 1
}
}
Dictionary is the best way I think. Have the key be the character and the value be the count of that character. Your runtime will be O(n) since you only have to run through each input once. Here is an example:
let chars = ["a","a","a","b","b","c","c","e","f","c"]
var dict = [String: Int]()
for char in chars {
//If already in Dictionary, increase by one
if var count = dict[char] {
count += 1
dict[char] = count
} else {//else is not in the dictionary already, init with 1
dict[char] = 1
}
}
Output:
["b": 2, "e": 1, "a": 3, "f": 1, "c": 3]
Now I'm not sure how you want to replace the value that's the same character for a third time, but this is probably the best way to group the strings to determine which are over the limit.
Instead of inserting the wrong value and then checking if the values are correct, I would suggest to automatically create the correct array.
//array for button names
var buttonValues = Array<String>()
//tracks what value has been inserted how many times
var trackerDict = [String: Int]()
for i in 0...9 {
//we initialize a new variable that tells us if we found a valid value (if the value has not been inserted 2 times already)
var foundValidValue = false
while !foundValidValue{
var val = NamePicker()
//now we check if the value exists and if it is inserted less than 2 times
if let count = trackerDict[val] {
if count < 2 {
foundValidValue = true
}
}
//if we found the value, we can add it
if foundValidValue {
trackerDict[val] = (trackerDict[val] ?? 0) + 1
buttonValues.append(val)
}
//if we did not find it, we just run through the loop again
}
}
I added a dictionary because it is faster to keep track of the count in a dictionary than counting the number of occurrences in the array every time.
So I have an array of elements of type float. And I have a UILabel which is supposed to display each of these elements of the array on DIFFERENT LINES.
The Array is
var history = [Float]()
I used a for loop to go through each element and append it to the UILabel
for(i=0; i<size; i++){
currentString = String(history[i])
result.text = result.text! + "\n" + currentString
}
result is the UILabel.
I tried using \n but it doesn't seem to recognise it. Any solutions for this in Swift. Thanks in advance!
You can try below to solve your issue.
let history = [1.0, 2.0, 3.0, 4.0]
var result = ""
self.lbl.text = ""
for var i=0; i < history.count; i++
{
let currentString = NSString(format: "%.2f", history[i])
self.lbl.text = self.lbl.text! + "\n" + (currentString as String)
}
And Line Number should be 0. I set that from XIB.
Thanks
The first thing I would check is if your label has (it is stupid mistake, but can happen to all of us)
label.numberOfLines = 0
Assuming that is true, instead of building the string by hand, you could use in-built function join(). Sadly, since it is not String array, you can't use it directly, but you have to create string array first
// Get both storages
var history = [Float]() // Filled with your data
var stringHistory = [String]()
// Convert each number to string
for value in history {
stringHistory.append(String(value))
}
// Finally, join array to one string using \n as separator
let finalString = "\n".join(stringHistory)
Hope some of this helps!
I am trying to fill in a table view from a dictionary data source and tried a lot to achieve desired result but lot of error, need help on this:
this is my test code in playground which almost gives me desired result, but when i try to do same thing in project nothing works:
I have marked my questions next to problem command line:
var sections = Dictionary<String, Array<String>>()
var mySId = ["s1","s2"]
var m``Sdate = ["jun1", "jun2"]
var mEdate = ["jun2", "jun4"]
var mytotalArr = [String]()
var index = 0
for myId in myScId {
mytotalArr.append(mSdate[index]) // transfer data to total array to group
mytotalArr.append(mEdate[index]) // tarnsfer data to total array to group
sections["\(myScId[index])"] = mytotalArr
index++
}
println(sections["sch1"]!) // "[jun1, jun1]"
// in project i do it like this
in cellForRowAtIndexPath
var myarr = sections[indexpath.section]
when i do same as above in project error message // Unresolved Identified indexPath
var mystring = sections["sch1"]!
println(mystring[1]) // "jun1"
Or Please suggest a way to achieve the result as below
Section header = Sch1 ,
row1 = jun1 // mSdate ,
row2 = jun2 // mEdate
section header = Sch2 ,
row1 = jun2 ,
row2 = jun4
Solution for this was not simple to figure out, but i managed using other Stack's.
Basically first you get the value from your first key in Dict, and that search for data witihin it.
little overkill on system and coding, but it works.
I know I can initialize an array of Ints for example like:
var intArray = [Int](count: 10, repeatedValue: 0)
What I want to do is something like this:
var array = Array(count:6, repeatedValue:Array(count:0, repeatedValue:AnyObject()))
(Xcode returns with: AnyObject cannot be constructed because it has no accessible initializers)
With the same outcome as I could initialize the array like:
var anyObjectArray : [[AnyObject]] = [[],[],[],[],[],[]]
But doing the above is ugly if i need like 100 rows of lets say 3
The problem is I can append in my function like:
// init array
var anyObjectArray : [[AnyObject]] = [[],[],[]]
//inside a for loop
anyObjectArray[i].append(someValue)
That works ok, until of course i gets higher then the number of rows in the array.
A answer to this problem is also acceptable if I could do something like:
anyObjectArray[append a empty row here][]
But that is probably stupid :)
I hope there is a way to do this cause I don't feel like having a line like:
var anyObjectArray : [[AnyObject]] = [ [],[],[],[],[],[],[],[],[],[],[],[],[],[],[], ... etc ]
at the top of my page ;)
Thank you for your time!
You don't need the second repeatedValue initialiser, since you want an empty array. You can just use
var array = Array(count:6, repeatedValue:[AnyObject]())
You can try with 2 loops, working as a grid :
var items: = Array<Array<Item>>()
for col in 0..<maxCol {
var colItems = Array<Item>()
for row in 0..<maxRow {
colItems.append(Item())
}
items.append(colItems)
}
//Append as much as you want after
Try this
let columns = 27
let rows = 52
var array = Array<Array<Double>>()
for column in 0... columns {
array.append(Array(count:rows, repeatedValue:Int()))
}
Try using this
let array = Array(count:6, repeatedValue:[])
for (var i=0; i<array.count; i++){
array[i] = Array(count:0, repeatedValue: AnyObject.self)
}
in place of your code.
Swift 3:
var array = Array(repeating:[AnyObject](),count:6)