The Curious Case of the Missing IEnumerable ForEach Extension

A recent discussion about C#'s lack of a Zip function sparked a related question: why doesn't C# provide a ForEach extension method for the widely used IEnumerable interface? Intriguingly, only List includes this functionality.

Unraveling the Mystery

Is this omission a performance optimization? Or is there a deeper, underlying reason? Several theories attempt to explain this noticeable gap.

The Built-in foreach Advantage

One perspective suggests that C#'s built-in foreach statement adequately addresses most iteration needs. Its concise and readable syntax is often preferred:

foreach (Item item in list)
{
    item.DoSomething();
}

This contrasts with the more verbose syntax of an extension method:

list.ForEach(item => item.DoSomething());

Arguments for a ForEach Extension

However, others argue for the practical benefits of a ForEach() extension method in specific situations. These benefits include:

• Improved Type Safety: An extension method offers compile-time type checking, unlike the runtime checking of the foreach statement.
• Streamlined Syntax: It simplifies invoking delegates, as demonstrated by "objects.ForEach(DoSomething);".
• Method Chaining Potential: While potentially prone to overuse, the ability to chain ForEach() calls is a compelling advantage.

A Shift in Perspective

Initially doubtful, some now recognize the value of a ForEach() extension method in certain scenarios. This reevaluation suggests that Microsoft might consider adding a standardized ForEach method in future framework releases.

The absence of this extension method for IEnumerable remains a topic of discussion. Given the potential advantages, the developer community anticipates further developments, hoping to see this gap addressed in the C# extension library.