how to convert foreach loop to lambda expression in c#

Question

foreach (IndexingField field in document.IndexingFields)
{
    if (field.TableColumn.ToLower() == "esig"&& field.Data != null && !string.IsNullOrEmpty(field.Data.ToString()) && field.Data.ToString() != "N")
    {                               
        EsigBase64Value = field.Data.ToString();
        field.Data = "Y";                                
    }                    
}

this is for each loop i am using , i would like to convert this for each loop to lambda expression ,please help me on this

Why? What is the actual question? You can convert the *contents* of a loop into a lambda and call it but that lambda will look no different from a method or even a local method. If you want to clean up your code, extract the loop block's code into a separate method — Panagiotis Kanavos, Jul 01 '21 at 07:47
What is `EsigBase64Value`? The way the code is written, it will only contain the contents of the last field after the loop. This is almost certainly a bug — Panagiotis Kanavos, Jul 01 '21 at 07:48
[Related](https://stackoverflow.com/q/225937/1997232). TLDR; you can use `ToList().ForEach()` combo or create extension method yourself. — Sinatr, Jul 01 '21 at 07:50
What is `field.Data`'s type? Why the calls to `ToString()`? `field.Data.ToString() != "N"` will only work if `Data` is *already* a `string`. The `if` condition could be simplified a *lot* — Panagiotis Kanavos, Jul 01 '21 at 07:52
field.data is of different types(int,bool,string etc..,).when table column is esig ,it will be of string data type and we need that value of esig in EsigBase64Value — chandra, Jul 01 '21 at 07:57

score 5 · Answer 1 · answered Jul 01 '21 at 07:46

Loops and lambda expressions are different things with different purposes. There is no lambda expression that correlates directly with this intent, and regular LINQ methods like Select are intended to perform projections (creating new data), not mutations (changing existing data).

In short: leave the code alone - it is fine as-is. My main observation would be what the value of EsigBase64Value is intended to be when there are zero or multiple records that match the if test. You might also want to hoist the field.Data.ToString() value, so it only happens once:

var data = field.Data.ToString();
if (...)
{

}

(using data in each place where field.Data.ToString() appears)

and maybe use a case-insensitive overload of string.Equals rather than field.TableColumn.ToLower() == "esig"

H.Sarxha · Answer 2 · 2021-07-01T09:56:28.310

1

You can use .Where

var field = document.IndexingFields.Where(f => f.TableColumn.ToLower() == "esig" && f.Data != null && !string.IsNullOrEmpty(f.Data.ToString()) && f.Data.ToString() != "N").FirstOrDefault();

And after that you can check with if condition

if (field != null)
 {
   EsigBase64Value = field.Data.ToString();
    field.Data = "Y";    
 }

edited Jul 01 '21 at 09:56

answered Jul 01 '21 at 08:36

H.Sarxha

157
1
9

i have tried above statements.in field we are not getting data property – chandra Jul 01 '21 at 09:53
@chandra you can try to reduce the checking for null or empty value, some of those are not necessary, for example ```!string.IsNullOrEmpty(f.Data.ToString())``` – H.Sarxha Jul 01 '21 at 09:56
see i am not getting issue with those conditions, we are getting data in field which is of var data type .in that field i am not getting property which is field.data – chandra Jul 01 '21 at 10:06
@chandra did u use ```.FirstOrDefault()``` ? – H.Sarxha Jul 01 '21 at 10:12
thank you so much it is working after using first or default – chandra Jul 01 '21 at 14:14
@chandra can you mark it as an answer please, so we can help others – H.Sarxha Jul 02 '21 at 07:55

how to convert foreach loop to lambda expression in c#

2 Answers2