Merge few lists into dictionary - ios

Question

I have 3 lists:
a = ["John", "Archie", "Levi"]
b = ["13", "20"]
c = ["m", "m", "m", "m"]
I want to merge this into one list with dictionaries:
result = [
{"name": "John", "age": "13", "gender": "m"},
{"name": "Archie", "age": "20", "gender": "m"},
{"name": "Levi", "age": "", "gender": "m"},
{"name": "", "age": "", "gender": "m"},
]

Answer 1

Ok, this is pretty normal computer science problem. Here is an outline of how to go about solving it:
First, identify the inputs and the desired outputs. You've done that.
Note any edge cases you need to handle
Next, map out the logic flow using pseudo-code.
Convert from pseudo-code to real code.
Test and debug.
For step 2, your data suggests that you want to handle cases where you have different numbers of elements in each source array. it looks like you want to create a dictionary for all the 0 elements in each array, then a dictionary for the 1 elements, etc. When you run out of elements for a given array, it looks like you want to skip that key in your resulting dictionary entry.
Now to pseudo-code:
Find the array with the maximum number of elements. Make this your output_count (the number of items in your output array.)
Create an output array large enough for output_count entries.
Loop from 0 to output_count - 1.
create a dictionary variable
for each input array, if there are enough elements, add a key/value pair
for that array's key and the value at the current index. Otherwise skip
that key.
add the new dictionary to the end of your output array.
That should be enough to get you started. Now see if you can convert that pseudo-code to actual code, test it, and debug it. Report back here with your actual code, and feel free to ask for help if you get stuck getting your code working.

Answer 2

Try like this:
let a = ["John", "Archie", "Levi"]
let b = ["13", "20"]
let c = ["m", "m", "m", "m"]
var dicArray:[[String:String]] = []
for index in 0..<max(a.count,b.count,c.count) {
dicArray.append([:])
dicArray[index]["name"] = index < a.count ? a[index] : ""
dicArray[index]["age"] = index < b.count ? b[index] : ""
dicArray[index]["gender"] = index < c.count ? c[index] : ""
}
dicArray // [["gender": "m", "age": "13", "name": "John"], ["gender": "m", "age": "20", "name": "Archie"], ["gender": "m", "age": "", "name": "Levi"], ["gender": "m", "age": "", "name": ""]]

Answer 3

Here is my take. I first create the array, and then use enumerate() and forEach to process each array and add them to the array of dictionaries:
let a = ["John", "Archie", "Levi"]
let b = ["13", "20"]
let c = ["m", "m", "m", "m"]
let count = max(a.count, b.count, c.count)
var result = Array(count: count, repeatedValue: ["name":"", "age":"", "gender":""])
a.enumerate().forEach { idx, val in result[idx]["name"] = val }
b.enumerate().forEach { idx, val in result[idx]["age"] = val }
c.enumerate().forEach { idx, val in result[idx]["gender"] = val }
print(result)
[["gender": "m", "age": "13", "name": "John"], ["gender": "m", "age":
"20", "name": "Archie"], ["gender": "m", "age": "", "name": "Levi"],
["gender": "m", "age": "", "name": ""]]

Answer 4

This should do the job
let maxLength = max(a.count, b.count, c.count)
let paddedA = a + [String](count: maxLength-a.count, repeatedValue: "")
let paddedB = b + [String](count: maxLength-b.count, repeatedValue: "")
let paddedC = c + [String](count: maxLength-c.count, repeatedValue: "")
let res = zip(paddedA, zip(paddedB, paddedC)).map {
["name": $0.0, "age": $0.1.0, "gender": $0.1.1]
}
Output
[["gender": "m", "age": "13", "name": "John"], ["gender": "m", "age": "20", "name": "Archie"], ["gender": "m", "age": "", "name": "Levi"], ["gender": "m", "age": "", "name": ""]]