How Lambda Expression works

Question

in an interview , interviewer ask me following query

int[] array = new[] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
Func<int, int> func = i =>
{
    Console.Write(array[i]);
    return i;
};

var result = array.Where(e => e <= func(2)).ToArray();

so will any one guide me how e <= func(2) thing works? and how last line i.e

var result = array.Where(e => e <= func(2)).ToArray();

works?

Answer 1

It may be easier to understand if you use parentheses:

var result = array.Where(e => (e <= func(2))).ToArray();

This

e => ...

Constructs a function which takes one argument.

This

e <= func(2)

compares e to func(2). func(2) calls the function func with the argument 2.

All in all, the <= has nothing to do with =>. They are two completely different operators. To summarize ... => ... constructs a function. ... <= ... compares the arguments.