Converting string to int from array

Question

I am trying to print out the exact location of an array element but am coming out short

string[] ocean = { "Beebo", "Jeff","Arthur", "Nemo", "Dory" };

foreach(string fish in ocean)
{
    if (fish == "Nemo")
    {
        Console.WriteLine("We found Nemo on position {0}!",int.Parse(fish));
        return;
    }
}

Console.WriteLine("He was not here");

I need the {0} token to be replaced with the array index of that element in this case with 3 but i am failing at the int.Parse(fish) which obviously isn't working

You could use Array.IndexOf to get the index of the fish name. Otherwise either use a for loop where you control the index or add a variable that you increment in the foreach to keep track of the index. — juharr
– juharr, Commented Jan 26, 2020 at 14:12
I haven't thought of multiple occurences, i only need the one occurence printed — Alter
– Alter, Commented Jan 26, 2020 at 14:17
All positions: string searchString = "Nemo"; int[] position = Enumerable.Range(0, ocean.Length).Where(idx => ocean[idx].Equals(searchString)).ToArray(); — Jimi
– Jimi, Commented Jan 26, 2020 at 14:38

juharr · Accepted Answer · 2020-01-26 17:11:08Z

4

The easiest way to get this working is by switching to a for loop

for(int i = 0; i < ocean.Length; i++)
{
    if (ocean[i] == "Nemo")
    {
        Console.WriteLine("We found Nemo on position {0}!", i);
        return;
    }
}
Console.WriteLine("He was not here");

Alternatively you can keep track of the index in a foreach

int index = 0;
foreach(string fish in ocean)
{
    if (fish == "Nemo")
    {
        Console.WriteLine("We found Nemo on position {0}!", index);
        return;
    }

    index++;
}
Console.WriteLine("He was not here");

Or you can avoid the loop altogether and use Array.IndexOf. It will return -1 if the value is not found.

int index = Array.IndexOf(ocean, "Nemo");
if(index >= 0)
    Console.WriteLine("We found Nemo on position {0}!", index);
else
    Console.WriteLine("He was not here");

And here's a Linq solution

var match = ocean.Select((x, i) => new { Value = x, Index = i })
    .FirstOrDefault(x => x.Value == "Nemo");
if(match != null)
    Console.WriteLine("We found Nemo on position {0}!", match.Index);
else
    Console.WriteLine("He was not here");

edited Jan 26, 2020 at 17:11

answered Jan 26, 2020 at 14:18

juharr

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2 Comments

Alter Over a year ago

Thank you very much but this was already known to me. I had my heart on a foreach this time

juharr Over a year ago

@Ale I've added a foreach solution and one that uses Array.IndexOf. I also tend to prefer foreach loops, but when I also need the index I almost always end up going back to the for loop instead.

Mahyar Mottaghi Zadeh · Accepted Answer · 2021-02-02 11:16:07Z

1

I am writing the probable solution in LINQ maybe and I hope it will be helpful. The error is due to the fact that indices in arrays start on zero it shows 3

   string[] ocean = { "Beebo", "Jeff","Arthur", "Nemo", "Dory" };

   ocean.Select((x, i) => new { Value = x, Index = i }).ForEach(element =>
   {
       if (element.Value == "Nemo")
       {
           Console.WriteLine("We found Nemo on position {0}!",element.Index);
       }
   });

How to use it in compiler

edited Feb 2, 2021 at 11:16

Mahyar Mottaghi Zadeh

1,3236 gold badges21 silver badges33 bronze badges

answered Jan 26, 2020 at 15:01

Reza Faghani

1611 silver badge12 bronze badges

10 Comments

juharr Over a year ago

A better Linq solution would be to use Where(x => x.Value == "Nemo").FirstOrDefault() and then you don't need to create a needless list with ToList just to use ForEach

Holger Over a year ago

good alternative, but it iterates twices through all elements, that's why it's not so efficient. And you can remove the ToList(), this isn't good for anything here.

juharr Over a year ago

@Holger The ToList is required to do the ForEach, but IMHO that's a horrible practice.

Holger Over a year ago

@juharr. Right, and your ideas misses the index. So if one wants to use LINQ, the answer is correct. Just to choose LINQ is not effective here.

juharr Over a year ago

Another issue with this solution is that it doesn't handle the case when no match is found.

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