Ttyjukl

Forgetting the musical notes while performing in concert

Is it possible to download Internet Explorer on my Mac running OS X El Capitan?

UK: Is there precedent for the governments e-petition site changing the direction of a government decision?

What exploit are these user agents trying to use?

What mechanic is there to disable a threat instead of killing it?

Can one be a co-translator of a book, if he does not know the language that the book is translated into?

Is the Joker left-handed?

Twin primes whose sum is a cube

AES: Why is it a good practice to use only the first 16bytes of a hash for encryption?

Did Shadowfax go to Valinor?

Can I use a neutral wire from another outlet to repair a broken neutral?

1960's book about a plague that kills all white people

Arrow those variables!

Is it possible to create light that imparts a greater proportion of its energy as momentum rather than heat?

Can I ask the recruiters in my resume to put the reason why I am rejected?

Reserved de-dupe rules

Is it unprofessional to ask if a job posting on GlassDoor is real?

Why is Collection not simply treated as Collection<?>

How could indestructible materials be used in power generation?

Does casting Light, or a similar spell, have any effect when the caster is swallowed by a monster?

Doing something right before you need it - expression for this?

Could gravitational lensing be used to protect a spaceship from a laser?

How badly should I try to prevent a user from XSSing themselves?

Neighboring nodes in the network

Combinations of multiple lists

How do I check if a list is empty?Finding the index of an item given a list containing it in PythonDifference between append vs. extend list methods in PythonHow to return multiple values from a function?How to make a flat list out of list of lists?How do I concatenate two lists in Python?How to clone or copy a list?How do I list all files of a directory?How to read a file line-by-line into a list?Catch multiple exceptions in one line (except block)

.everyoneloves__top-leaderboard:empty,.everyoneloves__mid-leaderboard:empty,.everyoneloves__bot-mid-leaderboard:empty{ height:90px;width:728px;box-sizing:border-box;
}

6

Suppose I have three lists:

list1 --> [a, b, c, d, e, f, g, h]

list2 --> [i, j, k]

list3 --> [l, m, n, o, p]

I wish to generate all combinations where I take five elements from list1, two elements from list2 and three elements from list3.

eg.

a, b, c, d, e, i, j, l, m, n  

a, b, c, d, e, i, j, l, m, o

etc.

I tried to use itertools.combinations.

l1_combinations = itertools.combinations(list1, 5)

l2_combinations = itertools.combinations(list2, 2)

l3_combinations = itertools.combinations(list3, 3)

for l1_iterator in list(l1_combinations):

    for l2_iterator in list(l2_combinations): #added a missing )

        for l3_iterator in list(l3_combinations):

            sample = l1_iterator + l2_iterator + l3_iterator

            print(sample)

But I am getting output with iterations happening only on list3. In all the output, only first five elements from list1 and first two elements from list2 are present. Combinations with other elements from those two lists aren't present.

Can someone help me here and also explain what exactly did i miss ?

python

share|improve this question

edited 1 hour ago

amchugh89

595621

asked 2 hours ago

Arun AranganathanArun Aranganathan

425

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Well I'm sure the missing ) in for l2_iterator in list(l2_combinations: doesn't help...
  
  – Reedinationer
  2 hours ago
  

  
  
  
  

add a comment | 

6

Suppose I have three lists:

list1 --> [a, b, c, d, e, f, g, h]

list2 --> [i, j, k]

list3 --> [l, m, n, o, p]

I wish to generate all combinations where I take five elements from list1, two elements from list2 and three elements from list3.

eg.

a, b, c, d, e, i, j, l, m, n  

a, b, c, d, e, i, j, l, m, o

etc.

I tried to use itertools.combinations.

l1_combinations = itertools.combinations(list1, 5)

l2_combinations = itertools.combinations(list2, 2)

l3_combinations = itertools.combinations(list3, 3)

for l1_iterator in list(l1_combinations):

    for l2_iterator in list(l2_combinations): #added a missing )

        for l3_iterator in list(l3_combinations):

            sample = l1_iterator + l2_iterator + l3_iterator

            print(sample)

But I am getting output with iterations happening only on list3. In all the output, only first five elements from list1 and first two elements from list2 are present. Combinations with other elements from those two lists aren't present.

Can someone help me here and also explain what exactly did i miss ?

python

share|improve this question

edited 1 hour ago

amchugh89

595621

asked 2 hours ago

Arun AranganathanArun Aranganathan

425

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Well I'm sure the missing ) in for l2_iterator in list(l2_combinations: doesn't help...
  
  – Reedinationer
  2 hours ago
  

  
  
  
  

add a comment | 

Suppose I have three lists:

list1 --> [a, b, c, d, e, f, g, h]

list2 --> [i, j, k]

list3 --> [l, m, n, o, p]

I wish to generate all combinations where I take five elements from list1, two elements from list2 and three elements from list3.

eg.

a, b, c, d, e, i, j, l, m, n  

a, b, c, d, e, i, j, l, m, o

etc.

I tried to use itertools.combinations.

l1_combinations = itertools.combinations(list1, 5)

l2_combinations = itertools.combinations(list2, 2)

l3_combinations = itertools.combinations(list3, 3)

for l1_iterator in list(l1_combinations):

    for l2_iterator in list(l2_combinations): #added a missing )

        for l3_iterator in list(l3_combinations):

            sample = l1_iterator + l2_iterator + l3_iterator

            print(sample)

But I am getting output with iterations happening only on list3. In all the output, only first five elements from list1 and first two elements from list2 are present. Combinations with other elements from those two lists aren't present.

Can someone help me here and also explain what exactly did i miss ?

python

share|improve this question

edited 1 hour ago

amchugh89

595621

asked 2 hours ago

Arun AranganathanArun Aranganathan

425

list1 --> [a, b, c, d, e, f, g, h]

list2 --> [i, j, k]

list3 --> [l, m, n, o, p]

a, b, c, d, e, i, j, l, m, n  

a, b, c, d, e, i, j, l, m, o

etc.

l1_combinations = itertools.combinations(list1, 5)

l2_combinations = itertools.combinations(list2, 2)

l3_combinations = itertools.combinations(list3, 3)

for l1_iterator in list(l1_combinations):

    for l2_iterator in list(l2_combinations): #added a missing )

        for l3_iterator in list(l3_combinations):

            sample = l1_iterator + l2_iterator + l3_iterator

            print(sample)

share|improve this question

edited 1 hour ago

amchugh89

595621

asked 2 hours ago

Arun AranganathanArun Aranganathan

425

share|improve this question

edited 1 hour ago

amchugh89

595621

asked 2 hours ago

Arun AranganathanArun Aranganathan

425

edited 1 hour ago

amchugh89

595621

edited 1 hour ago

amchugh89

595621

asked 2 hours ago

Arun AranganathanArun Aranganathan

425

asked 2 hours ago

Arun AranganathanArun Aranganathan

425

2 Answers
2

active

oldest

votes

7

As an alternative to regenerating the list of combinations, compute the product of the combinations up front; this also saves you from nesting for loops.

from itertools import combinations, product





list1 = list("abcdefgh")

list2 = list("ijk")

list3 = list("lmnop")



l1 = combinations(list1, 5)

l2 = combinations(list2, 2)

l3 = combinations(list3, 3)

for c1, c2, c3 in product(l1, l2, l3):

    sample = c1 + c2 + c3

    print(sample)

share|improve this answer

answered 1 hour ago

chepnerchepner

260k34250343

add a comment | 

6

Don't iterate over the same iterator multiple times, after the first time it's exhausted. Iterate over a fresh iterator each time:

for l1_iterator in itertools.combinations(list1, 5):

    for l2_iterator in itertools.combinations(list2, 2):

        for l3_iterator in itertools.combinations(list3, 3):

            sample = l1_iterator + l2_iterator + l3_iterator

            print(sample)

Or make lists of each one in advance to avoid recomputation:

l1_combinations = list(itertools.combinations(list1, 5))

l2_combinations = list(itertools.combinations(list2, 2))

l3_combinations = list(itertools.combinations(list3, 3))

for l1_iterator in l1_combinations:

    for l2_iterator in l2_combinations:

        for l3_iterator in l3_combinations:

            sample = l1_iterator + l2_iterator + l3_iterator

            print(sample)

share|improve this answer

edited 1 hour ago

answered 2 hours ago

Alex HallAlex Hall

23k32053

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  What would be a solution to not regenerate the combinations every time?
  
  – ritlew
  1 hour ago
  

  
  
  
  


• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  
  @ritlew see edit.
  
  – Alex Hall
  1 hour ago
  

  
  
  
  

add a comment | 

Your Answer

StackExchange.ifUsing("editor", function () {
StackExchange.using("externalEditor", function () {
StackExchange.using("snippets", function () {
StackExchange.snippets.init();
});
});
}, "code-snippets");

StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "1"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});

function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});


}
});

draft saved

draft discarded

Sign up or log in

StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});

Sign up using Google

Sign up using Facebook

Sign up using Email and Password

Post as a guest

Name

Email

Required, but never shown

StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f55523811%2fcombinations-of-multiple-lists%23new-answer', 'question_page');
}
);

Post as a guest

Name

Email

Required, but never shown

7

As an alternative to regenerating the list of combinations, compute the product of the combinations up front; this also saves you from nesting for loops.

from itertools import combinations, product





list1 = list("abcdefgh")

list2 = list("ijk")

list3 = list("lmnop")



l1 = combinations(list1, 5)

l2 = combinations(list2, 2)

l3 = combinations(list3, 3)

for c1, c2, c3 in product(l1, l2, l3):

    sample = c1 + c2 + c3

    print(sample)

share|improve this answer

answered 1 hour ago

chepnerchepner

260k34250343

add a comment | 

7

As an alternative to regenerating the list of combinations, compute the product of the combinations up front; this also saves you from nesting for loops.

from itertools import combinations, product





list1 = list("abcdefgh")

list2 = list("ijk")

list3 = list("lmnop")



l1 = combinations(list1, 5)

l2 = combinations(list2, 2)

l3 = combinations(list3, 3)

for c1, c2, c3 in product(l1, l2, l3):

    sample = c1 + c2 + c3

    print(sample)

share|improve this answer

answered 1 hour ago

chepnerchepner

260k34250343

add a comment | 

As an alternative to regenerating the list of combinations, compute the product of the combinations up front; this also saves you from nesting for loops.

from itertools import combinations, product





list1 = list("abcdefgh")

list2 = list("ijk")

list3 = list("lmnop")



l1 = combinations(list1, 5)

l2 = combinations(list2, 2)

l3 = combinations(list3, 3)

for c1, c2, c3 in product(l1, l2, l3):

    sample = c1 + c2 + c3

    print(sample)

share|improve this answer

answered 1 hour ago

chepnerchepner

260k34250343

from itertools import combinations, product





list1 = list("abcdefgh")

list2 = list("ijk")

list3 = list("lmnop")



l1 = combinations(list1, 5)

l2 = combinations(list2, 2)

l3 = combinations(list3, 3)

for c1, c2, c3 in product(l1, l2, l3):

    sample = c1 + c2 + c3

    print(sample)

share|improve this answer

answered 1 hour ago

chepnerchepner

260k34250343

answered 1 hour ago

chepnerchepner

260k34250343

answered 1 hour ago

chepnerchepner

260k34250343

6

Don't iterate over the same iterator multiple times, after the first time it's exhausted. Iterate over a fresh iterator each time:

for l1_iterator in itertools.combinations(list1, 5):

    for l2_iterator in itertools.combinations(list2, 2):

        for l3_iterator in itertools.combinations(list3, 3):

            sample = l1_iterator + l2_iterator + l3_iterator

            print(sample)

Or make lists of each one in advance to avoid recomputation:

l1_combinations = list(itertools.combinations(list1, 5))

l2_combinations = list(itertools.combinations(list2, 2))

l3_combinations = list(itertools.combinations(list3, 3))

for l1_iterator in l1_combinations:

    for l2_iterator in l2_combinations:

        for l3_iterator in l3_combinations:

            sample = l1_iterator + l2_iterator + l3_iterator

            print(sample)

share|improve this answer

edited 1 hour ago

answered 2 hours ago

Alex HallAlex Hall

23k32053

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  What would be a solution to not regenerate the combinations every time?
  
  – ritlew
  1 hour ago
  

  
  
  
  


• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  
  @ritlew see edit.
  
  – Alex Hall
  1 hour ago
  

  
  
  
  

add a comment | 

6

Don't iterate over the same iterator multiple times, after the first time it's exhausted. Iterate over a fresh iterator each time:

for l1_iterator in itertools.combinations(list1, 5):

    for l2_iterator in itertools.combinations(list2, 2):

        for l3_iterator in itertools.combinations(list3, 3):

            sample = l1_iterator + l2_iterator + l3_iterator

            print(sample)

Or make lists of each one in advance to avoid recomputation:

l1_combinations = list(itertools.combinations(list1, 5))

l2_combinations = list(itertools.combinations(list2, 2))

l3_combinations = list(itertools.combinations(list3, 3))

for l1_iterator in l1_combinations:

    for l2_iterator in l2_combinations:

        for l3_iterator in l3_combinations:

            sample = l1_iterator + l2_iterator + l3_iterator

            print(sample)

share|improve this answer

edited 1 hour ago

answered 2 hours ago

Alex HallAlex Hall

23k32053

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  What would be a solution to not regenerate the combinations every time?
  
  – ritlew
  1 hour ago
  

  
  
  
  


• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  
  @ritlew see edit.
  
  – Alex Hall
  1 hour ago
  

  
  
  
  

add a comment | 

Don't iterate over the same iterator multiple times, after the first time it's exhausted. Iterate over a fresh iterator each time:

for l1_iterator in itertools.combinations(list1, 5):

    for l2_iterator in itertools.combinations(list2, 2):

        for l3_iterator in itertools.combinations(list3, 3):

            sample = l1_iterator + l2_iterator + l3_iterator

            print(sample)

Or make lists of each one in advance to avoid recomputation:

l1_combinations = list(itertools.combinations(list1, 5))

l2_combinations = list(itertools.combinations(list2, 2))

l3_combinations = list(itertools.combinations(list3, 3))

for l1_iterator in l1_combinations:

    for l2_iterator in l2_combinations:

        for l3_iterator in l3_combinations:

            sample = l1_iterator + l2_iterator + l3_iterator

            print(sample)

share|improve this answer

edited 1 hour ago

answered 2 hours ago

Alex HallAlex Hall

23k32053

for l1_iterator in itertools.combinations(list1, 5):

    for l2_iterator in itertools.combinations(list2, 2):

        for l3_iterator in itertools.combinations(list3, 3):

            sample = l1_iterator + l2_iterator + l3_iterator

            print(sample)

l1_combinations = list(itertools.combinations(list1, 5))

l2_combinations = list(itertools.combinations(list2, 2))

l3_combinations = list(itertools.combinations(list3, 3))

for l1_iterator in l1_combinations:

    for l2_iterator in l2_combinations:

        for l3_iterator in l3_combinations:

            sample = l1_iterator + l2_iterator + l3_iterator

            print(sample)

share|improve this answer

edited 1 hour ago

answered 2 hours ago

Alex HallAlex Hall

23k32053

answered 2 hours ago

Alex HallAlex Hall

23k32053

answered 2 hours ago

Alex HallAlex Hall

23k32053