How to assign value after increment Swift?

Question

var str = ["Franc": 2]
var a = 1
str["Franc"] = a += 1
print(str)

When I try this code i get an error on line "str["Franc"] = a += 1" that is "Cannot assign value of type '()' to type 'Int?'" How to solve this. I need it in single line Thank you in advance

Essentially a duplicate of [Multiple variable assignment in Swift](https://stackoverflow.com/questions/26155523/multiple-variable-assignment-in-swift). — Martin R, Jun 06 '20 at 07:53
See also [increment Error in swift 3](https://stackoverflow.com/questions/39704971/increment-error-in-swift-3) — Martin R, Jun 06 '20 at 07:54
What I mean is set value of "a" to dictionary and then increment. How can it possible in one line — Graycodder, Jun 06 '20 at 08:09

score 2 · Accepted Answer · answered Jun 06 '20 at 08:04

2

We can do this directly only in Objective C:

In Objective C:

[str setValue:[NSNumber numberWithInt:a+=1] forKey:@"Franc"];

In Swift

str["Franc"] = a
a += 1

answered Jun 06 '20 at 08:04

Wide Angle Technology

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This is the only possible way? – Graycodder Jun 06 '20 at 08:06

Jawad Ali · Answer 2 · 2020-06-06T08:11:35.830

1

You can increment number like this

str["Franc"]! = a ; a += 1

assign value

var str = ["Franc": 2]
str["Franc"]! += 1

and now str["Franc"] will returns 3

And if you want to avoid force unwrapping

str["Franc"] = (str["Franc"] ?? 0) + 1

Also you can do it using if let

if let num = str["Franc"] as? Double {
    str["Franc"] = num + 1
}

edited Jun 06 '20 at 08:11

answered Jun 06 '20 at 07:49

Jawad Ali

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What I mean is set value of "a" to dictionary and then increment. How can it possible in one line – Graycodder Jun 06 '20 at 08:06
1

`str["Franc"]! = a ; a += 1` thats how you can do it in one line ... – Jawad Ali Jun 06 '20 at 08:10

Joby Ingram-Dodd · Answer 3 · 2020-06-06T08:08:03.987

0

I don't think you can do this in a single line:

var str = ["Franc": 2]
var a = 1
str["Franc"] = a 
a += 1
print(str)

edited Jun 06 '20 at 08:08

answered Jun 06 '20 at 07:45

Joby Ingram-Dodd

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You didn't increment `a` in your answer, and it looks like it is something OP wants. – marcelovca90 Jun 06 '20 at 07:57
What I mean is set value of "a" to dictionary and then increment. How can it possible in one line – Graycodder Jun 06 '20 at 07:58
Ok my mistake miss read the question, so you want to add a to the dictionary then increment the dictionary value or then increment a? – Joby Ingram-Dodd Jun 06 '20 at 08:03
1

I don't think you can do both in a single line. – Joby Ingram-Dodd Jun 06 '20 at 08:07

How to assign value after increment Swift?

3 Answers3