Iterating Through a List and Conditionally Setting a Member - Comparison Of Approaches

I have a requirement to iterate through a list, and conditionally set a data item against each item in the collection:

Using the standard foreach iterator, this is trivial:

//standard iteration
foreach (LogFileDataItem lfd in logFileData)
{
    if (lfd.FileName.Equals(currentLine, StringComparison.OrdinalIgnoreCase))
    {
        lfd.SQLScriptExecuted = true;
    }
}

But it got me into thinking that this was an ideal opportunity to explore LINQ, so I refactored to above to:

foreach (LogFileDataItem lfd in 
         from logFileDataItem in logFileData
         where logFileDataItem.FileName.Equals(currentLine, StringComparison.OrdinalIgnoreCase)
         select logFileDataItem)
{
    lfd.SQLScriptExecuted = true;
}

Which, of course can be refactored into a lambda expression:

foreach (LogFileDataItem lfd in log开发者_如何学编程FileData.Where(item => item.FileName.Equals(currentLine, StringComparison.OrdinalIgnoreCase))
                                           .Select(item => item))
{
    lfd.SQLScriptExecuted = true;
}

So my question really is really, how different are they? Do any offer a significant advantage over any other?

Well, you can get rid of the "Select(item => item)" bit from the lambda version (as indeed the C# compiler would have done):

foreach (LogFileDataItem lfd in logFileData.Where(item => 
    item.FileName.Equals(currentLine, StringComparison.OrdinalIgnoreCase))

But basically, yes - they're all doing the same thing. I'd consider separating out the query from the foreach loop:

var relevantLogItems = logFileData.Where(...);
foreach (var lfd in relevantLogItems)
{
    ...
}

but again that won't actually change what occurs.