Getting the array key in a 'foreach' loop
How do I get the key of the current element in a foreach loop in C#?
For example:
PHP
foreach ($array as $key => $value)
{
echo("$value is assigned to key: $key");
}
What I'm trying to do in C#:
int[] values = { 5, 14, 29, 49, 99, 150, 999 };
foreach (int val in values)
{
if(search <= val && !stop)
{
// Set key to a variable
}
}
Grauenwolf's way is the most straightforward and performant way of doing this with an array:
Either use a for loop or create a temp variable that you increment on each pass.
Which would of course look like this:
int[] values = { 5, 14, 29, 49, 99, 150, 999 };
for (int key = 0; key < values.Length; ++key)
if (search <= values[key] && !stop)
{
// set key to a variable
}
With .NET 3.5 you can take a more functional approach as well, but it is a little more verbose at the site, and would likely rely on a couple support functions for visiting the elements in an IEnumerable. Overkill if this is all you need it for, but handy if you tend to do a lot of collection processing.
If you want to get at the key (read: index) then you'd have to use a for loop. If you actually want to have a collection that holds keys/values then I'd consider using a HashTable or a Dictionary (if you want to use Generics).
Dictionary<int, string> items = new Dictionary<int, string>();
foreach (int key in items.Keys)
{
Console.WriteLine("Key: {0} has value: {1}", key, items[key]);
}
Hope that helps, Tyler
With DictionaryEntry and KeyValuePair:
Based on
MSDN
IDictionary<string,string> openWith = new Dictionary<string,string>()
{
{ "txt", "notepad.exe" }
{ "bmp", "paint.exe" }
{ "rtf", "wordpad.exe" }
};
foreach (DictionaryEntry de in openWith)
{
Console.WriteLine("Key = {0}, Value = {1}", de.Key, de.Value);
}
// also
foreach (KeyValuePair<string,string> de in openWith)
{
Console.WriteLine("Key = {0}, Value = {1}", de.Key, de.Value);
}
Releated SO question: KeyValuePair VS DictionaryEntry
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