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











$endgroup$








  • 3




    $begingroup$
    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
    3 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
    2 hours 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
    1 hour ago








  • 2




    $begingroup$
    Since the days of Carl Friedrich Gauß we know that using a For loop to compute 50 * 51 is a pretty bad idea....
    $endgroup$
    – Henrik Schumacher
    35 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











$endgroup$








  • 3




    $begingroup$
    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
    3 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
    2 hours 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
    1 hour ago








  • 2




    $begingroup$
    Since the days of Carl Friedrich Gauß we know that using a For loop to compute 50 * 51 is a pretty bad idea....
    $endgroup$
    – Henrik Schumacher
    35 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 1 hour ago









MarcoB

36.6k556112




36.6k556112










asked 4 hours ago









Laura FigueroaLaura Figueroa

61




61








  • 3




    $begingroup$
    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
    3 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
    2 hours 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
    1 hour ago








  • 2




    $begingroup$
    Since the days of Carl Friedrich Gauß we know that using a For loop to compute 50 * 51 is a pretty bad idea....
    $endgroup$
    – Henrik Schumacher
    35 mins ago














  • 3




    $begingroup$
    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
    3 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
    2 hours 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
    1 hour ago








  • 2




    $begingroup$
    Since the days of Carl Friedrich Gauß we know that using a For loop to compute 50 * 51 is a pretty bad idea....
    $endgroup$
    – Henrik Schumacher
    35 mins ago








3




3




$begingroup$
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
3 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
3 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
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
2 hours 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
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
1 hour ago






2




2




$begingroup$
Since the days of Carl Friedrich Gauß we know that using a For loop to compute 50 * 51 is a pretty bad idea....
$endgroup$
– Henrik Schumacher
35 mins ago




$begingroup$
Since the days of Carl Friedrich Gauß we know that using a For loop to compute 50 * 51 is a pretty bad idea....
$endgroup$
– Henrik Schumacher
35 mins ago










2 Answers
2






active

oldest

votes


















4












$begingroup$

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









$endgroup$









  • 1




    $begingroup$
    +1 for the first sentence.
    $endgroup$
    – Henrik Schumacher
    37 mins ago



















1












$begingroup$

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









$endgroup$









  • 1




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










  • $begingroup$
    Thank you! I was looking for something like Total and I saw the Plus posting above, but haven't yet learned about @@ and such. I would have thought Map might work here (it does not). Anyway, yes Total[T] and Plus@@T are simpler and more elegant!
    $endgroup$
    – mjw
    3 mins ago











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2 Answers
2






active

oldest

votes








2 Answers
2






active

oldest

votes









active

oldest

votes






active

oldest

votes









4












$begingroup$

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









$endgroup$









  • 1




    $begingroup$
    +1 for the first sentence.
    $endgroup$
    – Henrik Schumacher
    37 mins ago
















4












$begingroup$

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









$endgroup$









  • 1




    $begingroup$
    +1 for the first sentence.
    $endgroup$
    – Henrik Schumacher
    37 mins ago














4












4








4





$begingroup$

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 3 hours ago









High Performance MarkHigh Performance Mark

538411




538411








  • 1




    $begingroup$
    +1 for the first sentence.
    $endgroup$
    – Henrik Schumacher
    37 mins ago














  • 1




    $begingroup$
    +1 for the first sentence.
    $endgroup$
    – Henrik Schumacher
    37 mins ago








1




1




$begingroup$
+1 for the first sentence.
$endgroup$
– Henrik Schumacher
37 mins ago




$begingroup$
+1 for the first sentence.
$endgroup$
– Henrik Schumacher
37 mins ago











1












$begingroup$

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









$endgroup$









  • 1




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










  • $begingroup$
    Thank you! I was looking for something like Total and I saw the Plus posting above, but haven't yet learned about @@ and such. I would have thought Map might work here (it does not). Anyway, yes Total[T] and Plus@@T are simpler and more elegant!
    $endgroup$
    – mjw
    3 mins ago
















1












$begingroup$

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









$endgroup$









  • 1




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










  • $begingroup$
    Thank you! I was looking for something like Total and I saw the Plus posting above, but haven't yet learned about @@ and such. I would have thought Map might work here (it does not). Anyway, yes Total[T] and Plus@@T are simpler and more elegant!
    $endgroup$
    – mjw
    3 mins ago














1












1








1





$begingroup$

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 2 hours ago









mjwmjw

3666




3666








  • 1




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










  • $begingroup$
    Thank you! I was looking for something like Total and I saw the Plus posting above, but haven't yet learned about @@ and such. I would have thought Map might work here (it does not). Anyway, yes Total[T] and Plus@@T are simpler and more elegant!
    $endgroup$
    – mjw
    3 mins ago














  • 1




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










  • $begingroup$
    Thank you! I was looking for something like Total and I saw the Plus posting above, but haven't yet learned about @@ and such. I would have thought Map might work here (it does not). Anyway, yes Total[T] and Plus@@T are simpler and more elegant!
    $endgroup$
    – mjw
    3 mins ago








1




1




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




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












$begingroup$
Thank you! I was looking for something like Total and I saw the Plus posting above, but haven't yet learned about @@ and such. I would have thought Map might work here (it does not). Anyway, yes Total[T] and Plus@@T are simpler and more elegant!
$endgroup$
– mjw
3 mins ago




$begingroup$
Thank you! I was looking for something like Total and I saw the Plus posting above, but haven't yet learned about @@ and such. I would have thought Map might work here (it does not). Anyway, yes Total[T] and Plus@@T are simpler and more elegant!
$endgroup$
– mjw
3 mins ago


















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