C#•3y ago

❔ LINQ

Does linq have its own replace method? If so, does it make a new string or modify? Also is there a way to replace a string without making new string?

Angius•8/25/23, 1:18 AM

Wym a replace method?

Angius•8/25/23, 1:18 AM

And no, strings are immutable

Angius•8/25/23, 1:18 AM

So unless you get into the

unsafe

unsafe

territory and start swapping bytes around... no, you can't change a string without making a new string

AAngius Wym a replace method?

mattuOP•8/25/23, 1:22 AM

.replace()

Angius•8/25/23, 1:22 AM

Yeah, and why would LINQ need this method? What would you want to replace with it?

Angius•8/25/23, 1:22 AM

Because string already does have a replace method

Mmattu Does linq have its own replace method? If so, does it make a new string or modif...

mtreit•8/25/23, 1:22 AM

What's your starting point? A list of strings?

mattuOP•8/25/23, 1:23 AM

yeah like words

mattuOP•8/25/23, 1:24 AM

i mean it's okay I think i know a way to work around something anyway

Angius•8/25/23, 1:24 AM

And you want to replace every

"dog"

"dog"

into

"cat"

"cat"

or some such?

["dog", "is", "dog"]

["dog", "is", "dog"]

into

["cat", "is", "cat"]

["cat", "is", "cat"]

for example?

mattuOP•8/25/23, 1:26 AM

yeah but i have it an a loop to find different words and it creates a new string everytime. so it would just return the latest string. The thing is I would want it to add on top of each other

mattuOP•8/25/23, 1:27 AM

and it replaces the string with user input

mtreit•8/25/23, 1:27 AM

In LINQ you can use Select to project an original sequence into a new sequence.

MODiX•8/25/23, 1:28 AM

mtreit

REPL Result: Success

            var strings = new List<string>() { "A", "B", "C" };
            var updated = strings.Select(x =>
            {
                if (x == "A")
                {
                    return "Z";
                }

                return x;
            });

            foreach (var s in updated)
            {
                Console.WriteLine(s);
            }

            var strings = new List<string>() { "A", "B", "C" };
            var updated = strings.Select(x =>
            {
                if (x == "A")
                {
                    return "Z";
                }

                return x;
            });

            foreach (var s in updated)
            {
                Console.WriteLine(s);
            }

Console Output

Z
B
C

Z
B
C

Compile: 787.350ms | Execution: 91.401ms | React with ❌ to remove this embed.

mtreit•8/25/23, 1:29 AM

If I was starting with a List I probably wouldn't use LINQ but if you want to, that's one way to approach it.

mattuOP•8/25/23, 1:29 AM

oh alr

mattuOP•8/25/23, 1:29 AM

what if you wanted to change a and c

mtreit•8/25/23, 1:29 AM

Add more logic inside the lambda

Angius•8/25/23, 1:30 AM

You could define a dictionary of replacements too

MODiX•8/25/23, 1:30 AM

mtreit

REPL Result: Success

var strings = new List<string>() { "A", "B", "C" };
var updated = strings.Select(x =>
{
    return x switch
    {
        "A" => "Z",
        "C" => "Y",
        _ => x
    };
});

foreach (var s in updated)
{
    Console.WriteLine(s);
}

var strings = new List<string>() { "A", "B", "C" };
var updated = strings.Select(x =>
{
    return x switch
    {
        "A" => "Z",
        "C" => "Y",
        _ => x
    };
});

foreach (var s in updated)
{
    Console.WriteLine(s);
}

Console Output

Z
B
Y

Z
B
Y

Compile: 759.774ms | Execution: 154.762ms | React with ❌ to remove this embed.

Angius•8/25/23, 1:31 AM

Or a switch expression, even better, yea

mattuOP•8/25/23, 1:31 AM

yeah that's good

mattuOP•8/25/23, 1:31 AM

thanks guys

Mmtreit If I was starting with a List I probably wouldn't use LINQ but if you want to, t...

Thalnos•8/25/23, 1:24 PM

why wouldn't you use Linq when its a list?

TThalnos why wouldn't you use Linq when its a list?

mtreit•8/25/23, 4:22 PM

Performance

Mmtreit Performance

Thalnos•8/25/23, 4:22 PM

could you ellaborate a little more?

mtreit•8/25/23, 4:29 PM

LINQ in general is not great for performance so my first inclination is to avoid it if there is a trivial way to achieve the same thing. In most cases it probably doesn't matter much, but I am used to working on projects where performance is very important and the amount of data is large so LINQ is something I tend to avoid.

Accord•8/26/23, 4:39 PM

Was this issue resolved? If so, run

/close

/close

otherwise I will mark this as stale and this post will be archived until there is new activity.