For Loop and Sum












1












$begingroup$


I am requested to do a sum of the first fifty positive even numbers by using For loop.
The For loop that I created is 



For[natNum = 2, natNum <= 50, natNum = natNum + 2, Print[natNum]]


The output of this is a list of numbers from 2 to 50 and they are increasing by 2. Now I need these numbers to be sum so I created 



Sum[For[natNum = 2, natNum <= 50, natNum = natNum + 2, Print[natNum]]]


However, it is not a correct input. I am not sure if I should write the Sum inside the For loop.






homework







share|improve this question











$endgroup$








  • 2




    $begingroup$
    If this is a class assignment, I'd suggest withdrawing from the class. For loops are almost never a good way to do anything in Mathematica.
    $endgroup$
    – John Doty
    2 hours ago










  • $begingroup$
    If you want the first 50 positive even numbers, I believe that is {2, 4, ..., 100}. The sum is (2+100) + (4+98) + ... + (50 + 52) = 102 * 25 = 2550.
    $endgroup$
    – mjw
    1 hour ago












  • $begingroup$
    Total@Range[2, 2*50, 2] would be pretty direct. Note also that Print prints its arguments, but does not return them (in fact, it returns Null).
    $endgroup$
    – MarcoB
    19 mins ago


















1












$begingroup$


I am requested to do a sum of the first fifty positive even numbers by using For loop.
The For loop that I created is 



For[natNum = 2, natNum <= 50, natNum = natNum + 2, Print[natNum]]


The output of this is a list of numbers from 2 to 50 and they are increasing by 2. Now I need these numbers to be sum so I created 



Sum[For[natNum = 2, natNum <= 50, natNum = natNum + 2, Print[natNum]]]


However, it is not a correct input. I am not sure if I should write the Sum inside the For loop.






homework







share|improve this question











$endgroup$








  • 2




    $begingroup$
    If this is a class assignment, I'd suggest withdrawing from the class. For loops are almost never a good way to do anything in Mathematica.
    $endgroup$
    – John Doty
    2 hours ago










  • $begingroup$
    If you want the first 50 positive even numbers, I believe that is {2, 4, ..., 100}. The sum is (2+100) + (4+98) + ... + (50 + 52) = 102 * 25 = 2550.
    $endgroup$
    – mjw
    1 hour ago












  • $begingroup$
    Total@Range[2, 2*50, 2] would be pretty direct. Note also that Print prints its arguments, but does not return them (in fact, it returns Null).
    $endgroup$
    – MarcoB
    19 mins ago
















1












1








1





$begingroup$


I am requested to do a sum of the first fifty positive even numbers by using For loop.
The For loop that I created is 



For[natNum = 2, natNum <= 50, natNum = natNum + 2, Print[natNum]]


The output of this is a list of numbers from 2 to 50 and they are increasing by 2. Now I need these numbers to be sum so I created 



Sum[For[natNum = 2, natNum <= 50, natNum = natNum + 2, Print[natNum]]]


However, it is not a correct input. I am not sure if I should write the Sum inside the For loop.






homework







share|improve this question











$endgroup$




I am requested to do a sum of the first fifty positive even numbers by using For loop.
The For loop that I created is 



For[natNum = 2, natNum <= 50, natNum = natNum + 2, Print[natNum]]


The output of this is a list of numbers from 2 to 50 and they are increasing by 2. Now I need these numbers to be sum so I created 



Sum[For[natNum = 2, natNum <= 50, natNum = natNum + 2, Print[natNum]]]


However, it is not a correct input. I am not sure if I should write the Sum inside the For loop.






homework




homework






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited 25 mins ago









MarcoB

36.6k556112




36.6k556112










asked 3 hours ago









Laura FigueroaLaura Figueroa

61




61








  • 2




    $begingroup$
    If this is a class assignment, I'd suggest withdrawing from the class. For loops are almost never a good way to do anything in Mathematica.
    $endgroup$
    – John Doty
    2 hours ago










  • $begingroup$
    If you want the first 50 positive even numbers, I believe that is {2, 4, ..., 100}. The sum is (2+100) + (4+98) + ... + (50 + 52) = 102 * 25 = 2550.
    $endgroup$
    – mjw
    1 hour ago












  • $begingroup$
    Total@Range[2, 2*50, 2] would be pretty direct. Note also that Print prints its arguments, but does not return them (in fact, it returns Null).
    $endgroup$
    – MarcoB
    19 mins ago
















  • 2




    $begingroup$
    If this is a class assignment, I'd suggest withdrawing from the class. For loops are almost never a good way to do anything in Mathematica.
    $endgroup$
    – John Doty
    2 hours ago










  • $begingroup$
    If you want the first 50 positive even numbers, I believe that is {2, 4, ..., 100}. The sum is (2+100) + (4+98) + ... + (50 + 52) = 102 * 25 = 2550.
    $endgroup$
    – mjw
    1 hour ago












  • $begingroup$
    Total@Range[2, 2*50, 2] would be pretty direct. Note also that Print prints its arguments, but does not return them (in fact, it returns Null).
    $endgroup$
    – MarcoB
    19 mins ago










2




2




$begingroup$
If this is a class assignment, I'd suggest withdrawing from the class. For loops are almost never a good way to do anything in Mathematica.
$endgroup$
– John Doty
2 hours ago




$begingroup$
If this is a class assignment, I'd suggest withdrawing from the class. For loops are almost never a good way to do anything in Mathematica.
$endgroup$
– John Doty
2 hours ago












$begingroup$
If you want the first 50 positive even numbers, I believe that is {2, 4, ..., 100}. The sum is (2+100) + (4+98) + ... + (50 + 52) = 102 * 25 = 2550.
$endgroup$
– mjw
1 hour ago






$begingroup$
If you want the first 50 positive even numbers, I believe that is {2, 4, ..., 100}. The sum is (2+100) + (4+98) + ... + (50 + 52) = 102 * 25 = 2550.
$endgroup$
– mjw
1 hour ago














$begingroup$
Total@Range[2, 2*50, 2] would be pretty direct. Note also that Print prints its arguments, but does not return them (in fact, it returns Null).
$endgroup$
– MarcoB
19 mins ago






$begingroup$
Total@Range[2, 2*50, 2] would be pretty direct. Note also that Print prints its arguments, but does not return them (in fact, it returns Null).
$endgroup$
– MarcoB
19 mins ago












2 Answers
2






active

oldest

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3












$begingroup$

Anyone asking you to write For loops in Mathematica for such a problem is a dolt. Nevertheless, here's how you might do that:



rslt = 0;

For[i = 0, i <= 50, i += 2, rslt += i];

rslt


And here's how someone with some familiarity with Mathematica might write it



Plus @@ Range[25]*2


Now, spend the time you were going to waste writing a For loop by reading the answers to this question Why should I avoid the For loop in Mathematica?






share|improve this answer









$endgroup$





















    0












    $begingroup$

    The first fifty positive integers can be computed with Table:



    Q = 0; (* Initialization)
    
T = Table[Q + k, {k, 2 Range[50]}]


    enter image description here



    We can sum up the values of T with Sum:



    Sum[T[[k]], {k, Range[50]}]


    2550






    share|improve this answer









    $endgroup$













    • $begingroup$
      Perhaps better / more idiomatic than your Sum approach would be using Total[T] or Plus@@T.
      $endgroup$
      – MarcoB
      21 mins ago











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    2 Answers
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    active

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    2 Answers
    2






    active

    oldest

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    active

    oldest

    votes






    active

    oldest

    votes









    3












    $begingroup$

    Anyone asking you to write For loops in Mathematica for such a problem is a dolt. Nevertheless, here's how you might do that:



    rslt = 0;
    
For[i = 0, i <= 50, i += 2, rslt += i];
    
rslt


    And here's how someone with some familiarity with Mathematica might write it



    Plus @@ Range[25]*2


    Now, spend the time you were going to waste writing a For loop by reading the answers to this question Why should I avoid the For loop in Mathematica?






    share|improve this answer









    $endgroup$


















      3












      $begingroup$

      Anyone asking you to write For loops in Mathematica for such a problem is a dolt. Nevertheless, here's how you might do that:



      rslt = 0;
      
For[i = 0, i <= 50, i += 2, rslt += i];
      
rslt


      And here's how someone with some familiarity with Mathematica might write it



      Plus @@ Range[25]*2


      Now, spend the time you were going to waste writing a For loop by reading the answers to this question Why should I avoid the For loop in Mathematica?






      share|improve this answer









      $endgroup$
















        3












        3








        3





        $begingroup$

        Anyone asking you to write For loops in Mathematica for such a problem is a dolt. Nevertheless, here's how you might do that:



        rslt = 0;
        
For[i = 0, i <= 50, i += 2, rslt += i];
        
rslt


        And here's how someone with some familiarity with Mathematica might write it



        Plus @@ Range[25]*2


        Now, spend the time you were going to waste writing a For loop by reading the answers to this question Why should I avoid the For loop in Mathematica?






        share|improve this answer









        $endgroup$



        Anyone asking you to write For loops in Mathematica for such a problem is a dolt. Nevertheless, here's how you might do that:



        rslt = 0;
        
For[i = 0, i <= 50, i += 2, rslt += i];
        
rslt


        And here's how someone with some familiarity with Mathematica might write it



        Plus @@ Range[25]*2


        Now, spend the time you were going to waste writing a For loop by reading the answers to this question Why should I avoid the For loop in Mathematica?







        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered 2 hours ago









        High Performance MarkHigh Performance Mark

        528411




        528411























            0












            $begingroup$

            The first fifty positive integers can be computed with Table:



            Q = 0; (* Initialization)
            
T = Table[Q + k, {k, 2 Range[50]}]


            enter image description here



            We can sum up the values of T with Sum:



            Sum[T[[k]], {k, Range[50]}]


            2550






            share|improve this answer









            $endgroup$













            • $begingroup$
              Perhaps better / more idiomatic than your Sum approach would be using Total[T] or Plus@@T.
              $endgroup$
              – MarcoB
              21 mins ago
















            0












            $begingroup$

            The first fifty positive integers can be computed with Table:



            Q = 0; (* Initialization)
            
T = Table[Q + k, {k, 2 Range[50]}]


            enter image description here



            We can sum up the values of T with Sum:



            Sum[T[[k]], {k, Range[50]}]


            2550






            share|improve this answer









            $endgroup$













            • $begingroup$
              Perhaps better / more idiomatic than your Sum approach would be using Total[T] or Plus@@T.
              $endgroup$
              – MarcoB
              21 mins ago














            0












            0








            0





            $begingroup$

            The first fifty positive integers can be computed with Table:



            Q = 0; (* Initialization)
            
T = Table[Q + k, {k, 2 Range[50]}]


            enter image description here



            We can sum up the values of T with Sum:



            Sum[T[[k]], {k, Range[50]}]


            2550






            share|improve this answer









            $endgroup$



            The first fifty positive integers can be computed with Table:



            Q = 0; (* Initialization)
            
T = Table[Q + k, {k, 2 Range[50]}]


            enter image description here



            We can sum up the values of T with Sum:



            Sum[T[[k]], {k, Range[50]}]


            2550







            share|improve this answer












            share|improve this answer



            share|improve this answer










            answered 1 hour ago









            mjwmjw

            3566




            3566












            • $begingroup$
              Perhaps better / more idiomatic than your Sum approach would be using Total[T] or Plus@@T.
              $endgroup$
              – MarcoB
              21 mins ago


















            • $begingroup$
              Perhaps better / more idiomatic than your Sum approach would be using Total[T] or Plus@@T.
              $endgroup$
              – MarcoB
              21 mins ago
















            $begingroup$
            Perhaps better / more idiomatic than your Sum approach would be using Total[T] or Plus@@T.
            $endgroup$
            – MarcoB
            21 mins ago




            $begingroup$
            Perhaps better / more idiomatic than your Sum approach would be using Total[T] or Plus@@T.
            $endgroup$
            – MarcoB
            21 mins ago


















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