For Loop and Sum












2












$begingroup$


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
    10 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
    8 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
    7 hours ago








  • 5




    $begingroup$
    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
    6 hours ago










  • $begingroup$
    Is it the first fifty that you want, or is it {2, 4, ..., 50}? The original question had both.
    $endgroup$
    – mjw
    3 hours ago
















2












$begingroup$


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
    10 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
    8 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
    7 hours ago








  • 5




    $begingroup$
    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
    6 hours ago










  • $begingroup$
    Is it the first fifty that you want, or is it {2, 4, ..., 50}? The original question had both.
    $endgroup$
    – mjw
    3 hours ago














2












2








2





$begingroup$


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 7 hours ago









MarcoB

36.6k556112




36.6k556112










asked 10 hours ago









Laura FigueroaLaura Figueroa

111




111








  • 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
    10 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
    8 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
    7 hours ago








  • 5




    $begingroup$
    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
    6 hours ago










  • $begingroup$
    Is it the first fifty that you want, or is it {2, 4, ..., 50}? The original question had both.
    $endgroup$
    – mjw
    3 hours 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
    10 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
    8 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
    7 hours ago








  • 5




    $begingroup$
    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
    6 hours ago










  • $begingroup$
    Is it the first fifty that you want, or is it {2, 4, ..., 50}? The original question had both.
    $endgroup$
    – mjw
    3 hours 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
10 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
10 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
8 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
8 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
7 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
7 hours ago






5




5




$begingroup$
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
6 hours 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
6 hours ago












$begingroup$
Is it the first fifty that you want, or is it {2, 4, ..., 50}? The original question had both.
$endgroup$
– mjw
3 hours ago




$begingroup$
Is it the first fifty that you want, or is it {2, 4, ..., 50}? The original question had both.
$endgroup$
– mjw
3 hours ago










2 Answers
2






active

oldest

votes


















8












$begingroup$

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









$endgroup$









  • 2




    $begingroup$
    +1 for the first sentence.
    $endgroup$
    – Henrik Schumacher
    7 hours ago



















3












$begingroup$

The first fifty positive integers can be computed with Table:



Q = 0; (* Initialization *)

T = Table[Q + k, {k, 2 Range[50]}]


output of the above code



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
    7 hours 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
    6 hours ago










  • $begingroup$
    I was a latecomer to @@ as well. When I was learning about it, it helped me to think about it as a way of "swapping heads" of expressions. So for instance, if you have {1, 2, 3}, its FullForm would be List[1, 2, 3]. If you then Apply Plus to it, i.e. Plus@@, you swap the Listhead for a Plus head, to give Plus[1, 2, 3]. Although it may seem like a niche application at first, once you get used to it, it is tremendously useful!
    $endgroup$
    – MarcoB
    5 hours ago












  • $begingroup$
    This is great, thank you! Just as I learned not to use For loops (especially on this Forum), and to Do use Do, I'll look for opportunities to Apply @@.
    $endgroup$
    – mjw
    4 hours ago











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2 Answers
2






active

oldest

votes








2 Answers
2






active

oldest

votes









active

oldest

votes






active

oldest

votes









8












$begingroup$

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









$endgroup$









  • 2




    $begingroup$
    +1 for the first sentence.
    $endgroup$
    – Henrik Schumacher
    7 hours ago
















8












$begingroup$

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









$endgroup$









  • 2




    $begingroup$
    +1 for the first sentence.
    $endgroup$
    – Henrik Schumacher
    7 hours ago














8












8








8





$begingroup$

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 10 hours ago









High Performance MarkHigh Performance Mark

578411




578411








  • 2




    $begingroup$
    +1 for the first sentence.
    $endgroup$
    – Henrik Schumacher
    7 hours ago














  • 2




    $begingroup$
    +1 for the first sentence.
    $endgroup$
    – Henrik Schumacher
    7 hours ago








2




2




$begingroup$
+1 for the first sentence.
$endgroup$
– Henrik Schumacher
7 hours ago




$begingroup$
+1 for the first sentence.
$endgroup$
– Henrik Schumacher
7 hours ago











3












$begingroup$

The first fifty positive integers can be computed with Table:



Q = 0; (* Initialization *)

T = Table[Q + k, {k, 2 Range[50]}]


output of the above code



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
    7 hours 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
    6 hours ago










  • $begingroup$
    I was a latecomer to @@ as well. When I was learning about it, it helped me to think about it as a way of "swapping heads" of expressions. So for instance, if you have {1, 2, 3}, its FullForm would be List[1, 2, 3]. If you then Apply Plus to it, i.e. Plus@@, you swap the Listhead for a Plus head, to give Plus[1, 2, 3]. Although it may seem like a niche application at first, once you get used to it, it is tremendously useful!
    $endgroup$
    – MarcoB
    5 hours ago












  • $begingroup$
    This is great, thank you! Just as I learned not to use For loops (especially on this Forum), and to Do use Do, I'll look for opportunities to Apply @@.
    $endgroup$
    – mjw
    4 hours ago
















3












$begingroup$

The first fifty positive integers can be computed with Table:



Q = 0; (* Initialization *)

T = Table[Q + k, {k, 2 Range[50]}]


output of the above code



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
    7 hours 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
    6 hours ago










  • $begingroup$
    I was a latecomer to @@ as well. When I was learning about it, it helped me to think about it as a way of "swapping heads" of expressions. So for instance, if you have {1, 2, 3}, its FullForm would be List[1, 2, 3]. If you then Apply Plus to it, i.e. Plus@@, you swap the Listhead for a Plus head, to give Plus[1, 2, 3]. Although it may seem like a niche application at first, once you get used to it, it is tremendously useful!
    $endgroup$
    – MarcoB
    5 hours ago












  • $begingroup$
    This is great, thank you! Just as I learned not to use For loops (especially on this Forum), and to Do use Do, I'll look for opportunities to Apply @@.
    $endgroup$
    – mjw
    4 hours ago














3












3








3





$begingroup$

The first fifty positive integers can be computed with Table:



Q = 0; (* Initialization *)

T = Table[Q + k, {k, 2 Range[50]}]


output of the above code



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]}]


output of the above code



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








edited 3 hours ago









Conor O'Brien

1034




1034










answered 8 hours ago









mjwmjw

3867




3867








  • 1




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










  • $begingroup$
    I was a latecomer to @@ as well. When I was learning about it, it helped me to think about it as a way of "swapping heads" of expressions. So for instance, if you have {1, 2, 3}, its FullForm would be List[1, 2, 3]. If you then Apply Plus to it, i.e. Plus@@, you swap the Listhead for a Plus head, to give Plus[1, 2, 3]. Although it may seem like a niche application at first, once you get used to it, it is tremendously useful!
    $endgroup$
    – MarcoB
    5 hours ago












  • $begingroup$
    This is great, thank you! Just as I learned not to use For loops (especially on this Forum), and to Do use Do, I'll look for opportunities to Apply @@.
    $endgroup$
    – mjw
    4 hours ago














  • 1




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










  • $begingroup$
    I was a latecomer to @@ as well. When I was learning about it, it helped me to think about it as a way of "swapping heads" of expressions. So for instance, if you have {1, 2, 3}, its FullForm would be List[1, 2, 3]. If you then Apply Plus to it, i.e. Plus@@, you swap the Listhead for a Plus head, to give Plus[1, 2, 3]. Although it may seem like a niche application at first, once you get used to it, it is tremendously useful!
    $endgroup$
    – MarcoB
    5 hours ago












  • $begingroup$
    This is great, thank you! Just as I learned not to use For loops (especially on this Forum), and to Do use Do, I'll look for opportunities to Apply @@.
    $endgroup$
    – mjw
    4 hours ago








1




1




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




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












$begingroup$
I was a latecomer to @@ as well. When I was learning about it, it helped me to think about it as a way of "swapping heads" of expressions. So for instance, if you have {1, 2, 3}, its FullForm would be List[1, 2, 3]. If you then Apply Plus to it, i.e. Plus@@, you swap the Listhead for a Plus head, to give Plus[1, 2, 3]. Although it may seem like a niche application at first, once you get used to it, it is tremendously useful!
$endgroup$
– MarcoB
5 hours ago






$begingroup$
I was a latecomer to @@ as well. When I was learning about it, it helped me to think about it as a way of "swapping heads" of expressions. So for instance, if you have {1, 2, 3}, its FullForm would be List[1, 2, 3]. If you then Apply Plus to it, i.e. Plus@@, you swap the Listhead for a Plus head, to give Plus[1, 2, 3]. Although it may seem like a niche application at first, once you get used to it, it is tremendously useful!
$endgroup$
– MarcoB
5 hours ago














$begingroup$
This is great, thank you! Just as I learned not to use For loops (especially on this Forum), and to Do use Do, I'll look for opportunities to Apply @@.
$endgroup$
– mjw
4 hours ago




$begingroup$
This is great, thank you! Just as I learned not to use For loops (especially on this Forum), and to Do use Do, I'll look for opportunities to Apply @@.
$endgroup$
– mjw
4 hours ago


















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5 This question already has an answer here: How do you calculate the likelihood of drawing certain cards in your opening hand? 3 answers There is a funny modern deck where you play Treasure Hunt, but you really need to have it on the starting hand. How many mulligans should I take, if my deck contains 60 cards and contains 4 copies of Treasure Hunt? magic-the-gathering probability share | improve this question asked Nov 23 '18 at 12:12 dan dan 152 4
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Alcedinidae

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Alcedinidae Martin-pêcheur à dos bleu ( Alcedo azurea ) Classification (COI) Règne Animalia Embranchement Chordata Sous-embr. Vertebrata Classe Aves Ordre Coraciiformes Famille Alcedinidae Rafinesque, 1815 Les Alcédinidés ou Alcedinidae forment une famille d'oiseaux plus connus sous les noms de martins-pêcheurs et martins-chasseurs. Sommaire 1 Description 2 Répartition et habitat 3 Systématique 3.1 Liste alphabétique des genres 3.2 Liste des espèces 4 Chez les Anciens : l'alcyon 4.1 Étymologie (Littré) 4.2 Oiseau « fabuleux » ? 5 Notes 6 Articles connexes 7 Liens externes 7.1 Bibliographie Description | Ce sont des oiseaux compacts de taille petite à moyenne (10 à 46 cm), au bec droit et long, en forme de poignard. Leurs pattes sont courtes, et ils portent un plumage aux couleurs vives. Répartition et habitat | Cosmopolites, ils fréquentent surtout
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Can an atomic nucleus contain both particles and antiparticles? [duplicate]

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9 $begingroup$ This question already has an answer here: What happens if we put together a proton and an antineutron? 2 answers Is it theoretically possible to make a "deuterium" atom containing a proton and an antineutron in its nucleus? Would the strong nuclear force cause attraction between a proton and an antineutron? Would such a nucleus be stable, or would the proton somehow annihilate the antineutron when close enough? nuclear-physics antimatter share | cite | improve this question asked yesterday
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