How to change List of strings using LINQ? [duplicate]

Question

I have this List of strings:

List<string> result = new List<string>();      

result.Add("dummy1");
result.Add("dummy2");
result.Add("dummy3");
result.Add("dummy4");

I want to change items in result variable to add some string posfix:

result[0]("dummy1-aaa");
result[1]("dummy2-aaa");
result[2]("dummy3-aaa");
result[3]("dummy4-aaa");

I know that I can use for loop iterate on result variable and put new string to the item.

But my question is how can I change it using LINQ to object?

Do you need to modify the existing list, or are you happy to create a new list? (LINQ is query-oriented; it doesn't provide modification capabilities in itself.) — Jon Skeet
– Jon Skeet, Commented Jun 18, 2018 at 12:30
strings are immutable, you'd be replacing an element with a new string really. — Josh Adams
– Josh Adams, Commented Jun 18, 2018 at 12:31
Try this. result.Select(r => string.Concat(r, "-aaa")).ToList(); — Rishi Malviya
– Rishi Malviya, Commented Jun 18, 2018 at 12:33
@Michael: It's not clear to me that that answers the question. You've now got two answers, neither of which modify the existing list - they both create new lists. If you have another variable with a reference to the existing list, that won't observe any changes with those "create a new list" options. — Jon Skeet
– Jon Skeet, Commented Jun 18, 2018 at 12:40

SᴇM · Accepted Answer · 2018-06-18 12:57:59Z

15

You can write something like this:

result = result.Select(s => $"{s}-aaa").ToList();

or below C#6

result = result.Select(s => string.Format("{0}-aaa", s)).ToList();

answered Jun 18, 2018 at 12:33

SᴇM

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3 Comments

what is meaning of $ ?

$ - is string interpolation character. String interpolation is turned into string.Format() at compile-time.

apomene · Accepted Answer · 2018-06-18 12:33:31Z

1

You can try, like:

var newList = result.Select(r=>r+"-aaa").ToList();

answered Jun 18, 2018 at 12:33

apomene

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