For example i have an array
var array = [1, 2, 3, 4]
I want to remove item at index 1 then at index 3 "let it be in a for loop".
But removing the item at index 1 will move the item at index 3 to index 2, thus messing up the second removal.
Any suggestions ?
Given your array
var numbers = [1, 2, 3, 4]
and a Set of indexes you want to remove
let indexesToRemove: Set = [1, 3]
You want to remove the values "2" and "4".
Just write
numbers = numbers
.enumerated()
.filter { !indexesToRemove.contains($0.offset) }
.map { $0.element }
Result
print(numbers) // [1, 3]
filter and map is using a single flatMap, e.g. ... .enumerate().flatMap { indexesToRemove.contains($0) ? nil : $1 } (same syntax Swift 2.2/3.0).filter+map possibly shows intent better, whereas flatMap can be just a little bit neater (imho) in cases where the operation within the map is somewhat trivial :) good to know both alternatives!It's simple. delete items from the end.
First delete 3 and after that delete 1
reloadData on the table? The table needs to know that the row count is now different.
I think the simplest way is removing from behind. So you don't have to worry about the changed index.
var numbers = [1, 2, 3, 4, 5]
let indexesToRemove = [1, 3]
indexesToRemove.sort(by: >)
for i in indexesToRemove {
numbers.remove(at:i)
}
Swift 3: Use swift closure to perform the same operation.
If your array is like
var numbers = [0, 1, 2, 3, 4, 5]
and indexes you want to remove
let indexesToBeRemoved: Set = [2, 4]
numbers = numbers
.enumerated()
.filter { !indexesToRemove.contains($0.offset) }
.map { $0.element }
and result
print(numbers) // [0, 1, 3, 5]
Swift 3: Here is same operation with JSON Object (dictionary)
var arrayString = [
[ "char" : "Z" ],
[ "char" : "Y" ],
[ "char" : "X" ],
[ "char" : "W" ],
[ "char" : "V" ],
[ "char" : "U" ],
[ "char" : "T" ],
[ "char" : "S" ]
]
let arrayIndex = [2, 3, 5]
arrayString = arrayString.enumerated()
.filter { !arrayIndex.contains($0.0 + 1) }
.map { $0.1 }
print(arrayString)
[["char": "Z"], ["char": "W"], ["char": "U"], ["name": "T"], ["name": "S"]]
