How to return multiple keyvalue pairs in c# using foreach loop? [duplicate]

Question

Currently I have written a logic to return multiple key value pairs using for each loop, but it's return just the first key-value pair. My current code is:

 public static string ReturnData(IEnumerable<KeyValuePair<string, string>> abc)
        {
            if (abc != null)
            {
                foreach (KeyValuePair<string, string> item in abc)
                {
                    return $"{{\"{item.Key}\":\"{item.Value}\"}}";
                 }
            return null;
            }
         }

Change the method return type to IEnumerable<string> and add the yield keyword before return inside the foreach loop — LoRdPMN
– LoRdPMN, Commented Apr 26, 2022 at 11:49
Do away with this method entirely, and use whatever value you supply into abc directly wherever you use it — Caius Jard
– Caius Jard, Commented Apr 26, 2022 at 11:51
Please do not vandalize your posts. By posting on the Stack Exchange network, you've granted a non-revocable right for SE to distribute that content (under the CC BY-SA 4.0 license). By SE policy, any vandalism will be reverted. — tripleee
– tripleee, Commented Apr 26, 2022 at 14:06
Somewhere else you have maybe var dict = new Dictionary<string, string>(){ ["a"] = "a" }; and you're calling foreach(string s in ReturnData(dict)) - just do foreach(string s in dict.Select(kvp => $"{{\"{item.Key}\":\"{item.Value}\"}}")) — Caius Jard
– Caius Jard, Commented Apr 26, 2022 at 16:11

TylerH · Accepted Answer · 2022-04-26 14:14:25Z

1

You can use an iterator block to return a list of items

public static IEnumerable<string> ReturnData(IEnumerable<KeyValuePair<string, string>> abc)
{
    if (abc != null)
    {
        foreach (KeyValuePair<string, string> item in abc)
        {
            yield return $"{{\"{item.Key}\":\"{item.Value}\"}}";
        }
    }
}

edited Apr 26, 2022 at 14:14

TylerH

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answered Apr 26, 2022 at 11:48

JonasH

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Comments

Dennis · Accepted Answer · 2022-04-26 11:58:17Z

0

Use Enumerable.Select extension:

abc.Select(item => $"{{\"{item.Key}\":\"{item.Value}\"}}");

If you still want to re-use this code, then re-write ReturnData like this:

public static IEnumerable<string> ReturnData(this IEnumerable<KeyValuePair<string, string>> abc)
{
    if (abc != null)
    {
        return abc.Select(item => $"{{\"{item.Key}\":\"{item.Value}\"}}");
    }

    return Enumrable.Empty<string>();
}

Note, that this turns ReturnData into an extension method, which allows to call it this way:

abc.ReturnData();

edited Apr 26, 2022 at 11:58

answered Apr 26, 2022 at 11:49

Dennis

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1 Comment

Caius Jard Over a year ago

Yea, and use it instead of ReturnData, rather than inside of ReturnData.. An $@ string with "" instead of \" might look cleaner

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