I have observed that Lambda Expressions got good steam among developers. It
helps us in reducing lot of code and save time.
I would like to list some of the useful Lambda Expressions here comparing with
the without-lambda approach.
Common Setup Code
Here the common initialization code for using the below examples are given:
List<int>
list =
new
List<int>(new
int[]
{ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10});
| Scenario |
Lambda Approach |
Traditional Approach |
| Descending Sort |
list.OrderByDescending(i
=> i); |
list.Sort(delegate(int
x,
int
y)
{
return
y.CompareTo(x);
}); |
|
Check all numbers are less than 100 |
bool
result = list.All(i
=> i < 100); |
bool
result =
true;
foreach
(int
i
in
list)
if
(i >= 100)
result =
false; |
|
Check any numbers are equal to 5 |
bool
result = list.Any(i => i == 5); |
bool
result =
false;
foreach
(int
i
in
list)
if
(i == 5)
result =
true; |
|
Get the top 5 items in the list |
var
sublist = list.Take(3); |
var
sublist =
new
List<int>();
for
(int
i = 0; i < 5; i++)
if
(i < list.Count)
sublist.Add(i); |
|
Sort descending, get all numbers less than 8, take the top 5 |
var
result = list.OrderByDescending(i => i).Where(i => i < 8).Take(5); |
list.Sort(delegate(int
x,
int
y)
{
return
y.CompareTo(x);
});
List<int>
result =
new
List<int>();
foreach
(int
i
in
list)
if
(i < 8)
if
(result.Count < 5)
result.Add(i); |
Summary
I think the examples above demonstrate how complex the code will look even if
you do the simple sorting and selection.
Surely Lambda Expressions is worth learning and in the long run it would give
more manageable code.
Note
In the sorting scenario above, the original list is not updated, OrderBy() will
be giving a sorted view of the original list.
For assigning it back to the original list we have to use the ToList<int>()
method as:
list = list.OrderByDescending(i => i).ToList<int>();