C List of objects how do I get the sum of a property

Question

I have a list of objects  One property of the individual object entry is amount  How do I get the sum of amount   If my list was of type double I may be able to do something like this   double total   myList Sum      However I want to something similar to this  yet this syntax is incorrect   double total   myList amount Sum      How should I go about accomplishing this  I would love to use the Sum function if possible instead of looping through and calculating the value

User · Answer

Another alternative   myPlanetsList Select i   gt  i Moons  Sum

User · Answer

using System Linq         double total   myList Sum item   gt  item Amount

User · Answer

Here is example code you could run to make such test   var f   10000000  var p   new int f    for int i   0  i  lt  f    i        p i    i   2     var time   DateTime Now  p Sum    Console WriteLine DateTime Now - time    int x   0  time   DateTime Now  foreach var item in p      x    item    Console WriteLine DateTime Now - time    x   0  time   DateTime Now  for int i   0  j   f  i  lt  j    i      x    p i     Console WriteLine DateTime Now - time     The same example for complex object is   void Main         var f   10000000      var p   new Test f        for int i   0  i  lt  f    i                p i    new Test            p i  Property   i   2             var time   DateTime Now      p Sum k   gt  k Property       Console WriteLine DateTime Now - time        int x   0      time   DateTime Now      foreach var item in p           x    item Property            Console WriteLine DateTime Now - time        x   0      time   DateTime Now      for int i   0  j   f  i  lt  j    i           x    p i  Property            Console WriteLine DateTime Now - time      class Test       public int Property   get  set        My results with compiler optimizations off are   00 00 00 0570370   Sum   00 00 00 0250180   Foreach   00 00 00 0430272   For        and for second test are   00 00 00 1450955   Sum   00 00 00 0650430   Foreach   00 00 00 0690510   For     it looks like LINQ is generally slower than foreach      but what is weird for me is that foreach      appears to be faster than for loop

User · Answer

And if you need to do it on items that match a specific condition     double total   myList Where item   gt  item Name     Eggs   Sum item   gt  item Amount

[c#] C# List of objects, how do I get the sum of a property

Examples related to c#

Examples related to list

Examples related to sum