>>>>>Hi All, is it possible in a "Linq type way" to set properties of class instances which are in a IList ? , for example I have a list of names and addresses in a list and if there are some that share a certain residential area code (e.g. UK ) I would like to set a property in the instances, hope this makes sense.
>>>>
>>>>Closest you can get is probably something like:

foreach(Info i in list.Where(x=>x.Postcode.StartsWith="HR"))
>>>>            {
>>>>                i.SomeProperty = true;
>>>>            }

>>>
>>>List does have a foreach method (http://msdn.microsoft.com/en-us/library/bwabdf9z%28v=vs.110%29.aspx), but its not really recommended (http://blogs.msdn.com/b/ericlippert/archive/2009/05/18/foreach-vs-foreach.aspx). There is also a parallel foreach (http://msdn.microsoft.com/en-us/library/dd992001%28v=vs.110%29.aspx) you could use if setting the value has no side effects.
>>
>>Not sure I agree with the arguments against .ForEach. Anyway, interesting that Reflector for ForEach shows::

public void ForEach(Action<T> action)
>>{
>>    if (action == null)
>>    {
>>        ThrowHelper.ThrowArgumentNullException(ExceptionArgument.match);
>>    }
>>    for (int i = 0; i < this._size; i++)
>>    {
>>        action(this._items[i]);
>>    }
>>}

and foreach:

public bool MoveNext()
>>{
>>    if (this.version != this.list._version)
>>    {
>>        ThrowHelper.ThrowInvalidOperationException(ExceptionResource.InvalidOperation_EnumFailedVersion);
>>    }
>>    if (this.index < this.list._size)
>>    {
>>        this.current = this.list._items[this.index];
>>        this.index++;
>>        return true;
>>    }
>>    this.index = this.list._size + 1;
>>    this.current = default(T);
>>    return false;
>>}

>
>
>fwiw
>
>(1) Think for( ; ; )is quicker than for each
>(2) Your reflector code of the ForEach shows it is using a for( ; ; )

I've a feeling we discussed this in a thread a long time ago :-}

So ? :
'for' is quicker (and you can break)
foreach() is more readable (and less error prone)