Length of a single sublist in python












1














Lets assume i have a list of 3 sublists



a = [[1,1,1],[1,1,1],[1,1,1]]


If I use the command len(a[0:2])
I get the answer 2 (Because there are two elements(sublists) in the list)



But when I do len(a[2]) and want to get the answer 1 (because there is only one element(sublist) in the list) I actually get the length of the third list (which is 3 in this case).



How could I solve this problem?






python list sublist







share|improve this question






















  • How about len(a[2:3])?
    – Loocid
    Nov 23 '18 at 1:13












  • len(a[2]) takes the length of the third element. len(a[0:2]) takes the number of elements in that range.
    – Cua
    Nov 23 '18 at 2:07
















1














Lets assume i have a list of 3 sublists



a = [[1,1,1],[1,1,1],[1,1,1]]


If I use the command len(a[0:2])
I get the answer 2 (Because there are two elements(sublists) in the list)



But when I do len(a[2]) and want to get the answer 1 (because there is only one element(sublist) in the list) I actually get the length of the third list (which is 3 in this case).



How could I solve this problem?






python list sublist







share|improve this question






















  • How about len(a[2:3])?
    – Loocid
    Nov 23 '18 at 1:13












  • len(a[2]) takes the length of the third element. len(a[0:2]) takes the number of elements in that range.
    – Cua
    Nov 23 '18 at 2:07














1












1








1







Lets assume i have a list of 3 sublists



a = [[1,1,1],[1,1,1],[1,1,1]]


If I use the command len(a[0:2])
I get the answer 2 (Because there are two elements(sublists) in the list)



But when I do len(a[2]) and want to get the answer 1 (because there is only one element(sublist) in the list) I actually get the length of the third list (which is 3 in this case).



How could I solve this problem?






python list sublist







share|improve this question













Lets assume i have a list of 3 sublists



a = [[1,1,1],[1,1,1],[1,1,1]]


If I use the command len(a[0:2])
I get the answer 2 (Because there are two elements(sublists) in the list)



But when I do len(a[2]) and want to get the answer 1 (because there is only one element(sublist) in the list) I actually get the length of the third list (which is 3 in this case).



How could I solve this problem?






python list sublist




python list sublist






share|improve this question













share|improve this question











share|improve this question




share|improve this question










asked Nov 23 '18 at 1:09









Kaur Kadak

143




143












  • How about len(a[2:3])?
    – Loocid
    Nov 23 '18 at 1:13












  • len(a[2]) takes the length of the third element. len(a[0:2]) takes the number of elements in that range.
    – Cua
    Nov 23 '18 at 2:07


















  • How about len(a[2:3])?
    – Loocid
    Nov 23 '18 at 1:13












  • len(a[2]) takes the length of the third element. len(a[0:2]) takes the number of elements in that range.
    – Cua
    Nov 23 '18 at 2:07
















How about len(a[2:3])?
– Loocid
Nov 23 '18 at 1:13






How about len(a[2:3])?
– Loocid
Nov 23 '18 at 1:13














len(a[2]) takes the length of the third element. len(a[0:2]) takes the number of elements in that range.
– Cua
Nov 23 '18 at 2:07




len(a[2]) takes the length of the third element. len(a[0:2]) takes the number of elements in that range.
– Cua
Nov 23 '18 at 2:07












3 Answers
3






active

oldest

votes


















0














You need to use len(a[2:3]): 



 a = [[1,2,3],[4,5,6],[7,8,9]]



a[2]

>>> [7, 8, 9] 



len(a[2])

>>> 3



a[2:3]

>>> [[7, 8, 9]] 



len(a[2:3])

>>> 1





share|improve this answer

















  • 1




    Thank, that works perfectly! I thought that len(a[2:3]) would be out of the list range because the list doesn't have anything on index 3 but I was mistaken.
    – Kaur Kadak
    Nov 23 '18 at 14:09



















0














You have to specify the range you want to look at.



len(a[1:2]) should do the trick.



len(a[x:y]) simply means "the length of a from element x to y (non-inclusive)"



So if you do len(a[2:2]) the output is 0.






share|improve this answer





























    0














    You can use:



    print(len(a[2:3]))


    Or if want it builtin, do a function:



    _len=len
    
def len(l):
    
    if _len(l)==0:
    
        return 0
    
    elif isinstance(l[0],list):
    
        return _len(l)
    
    return _len([l])
    

    
a=[[1,1,1],[1,1,1],[1,1,1]]
    
print(len(a[2]))


    Both Output:



    1





    share|improve this answer





















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      3 Answers
      3






      active

      oldest

      votes








      3 Answers
      3






      active

      oldest

      votes









      active

      oldest

      votes






      active

      oldest

      votes









      0














      You need to use len(a[2:3]): 



       a = [[1,2,3],[4,5,6],[7,8,9]]
      

      
a[2]
      
>>> [7, 8, 9] 
      

      
len(a[2])
      
>>> 3
      

      
a[2:3]
      
>>> [[7, 8, 9]] 
      

      
len(a[2:3])
      
>>> 1





      share|improve this answer

















      • 1




        Thank, that works perfectly! I thought that len(a[2:3]) would be out of the list range because the list doesn't have anything on index 3 but I was mistaken.
        – Kaur Kadak
        Nov 23 '18 at 14:09
















      0














      You need to use len(a[2:3]): 



       a = [[1,2,3],[4,5,6],[7,8,9]]
      

      
a[2]
      
>>> [7, 8, 9] 
      

      
len(a[2])
      
>>> 3
      

      
a[2:3]
      
>>> [[7, 8, 9]] 
      

      
len(a[2:3])
      
>>> 1





      share|improve this answer

















      • 1




        Thank, that works perfectly! I thought that len(a[2:3]) would be out of the list range because the list doesn't have anything on index 3 but I was mistaken.
        – Kaur Kadak
        Nov 23 '18 at 14:09














      0












      0








      0






      You need to use len(a[2:3]): 



       a = [[1,2,3],[4,5,6],[7,8,9]]
      

      
a[2]
      
>>> [7, 8, 9] 
      

      
len(a[2])
      
>>> 3
      

      
a[2:3]
      
>>> [[7, 8, 9]] 
      

      
len(a[2:3])
      
>>> 1





      share|improve this answer












      You need to use len(a[2:3]): 



       a = [[1,2,3],[4,5,6],[7,8,9]]
      

      
a[2]
      
>>> [7, 8, 9] 
      

      
len(a[2])
      
>>> 3
      

      
a[2:3]
      
>>> [[7, 8, 9]] 
      

      
len(a[2:3])
      
>>> 1






      share|improve this answer












      share|improve this answer



      share|improve this answer










      answered Nov 23 '18 at 1:18









      Julian Peller

      864511




      864511








      • 1




        Thank, that works perfectly! I thought that len(a[2:3]) would be out of the list range because the list doesn't have anything on index 3 but I was mistaken.
        – Kaur Kadak
        Nov 23 '18 at 14:09














      • 1




        Thank, that works perfectly! I thought that len(a[2:3]) would be out of the list range because the list doesn't have anything on index 3 but I was mistaken.
        – Kaur Kadak
        Nov 23 '18 at 14:09








      1




      1




      Thank, that works perfectly! I thought that len(a[2:3]) would be out of the list range because the list doesn't have anything on index 3 but I was mistaken.
      – Kaur Kadak
      Nov 23 '18 at 14:09




      Thank, that works perfectly! I thought that len(a[2:3]) would be out of the list range because the list doesn't have anything on index 3 but I was mistaken.
      – Kaur Kadak
      Nov 23 '18 at 14:09













      0














      You have to specify the range you want to look at.



      len(a[1:2]) should do the trick.



      len(a[x:y]) simply means "the length of a from element x to y (non-inclusive)"



      So if you do len(a[2:2]) the output is 0.






      share|improve this answer


























        0














        You have to specify the range you want to look at.



        len(a[1:2]) should do the trick.



        len(a[x:y]) simply means "the length of a from element x to y (non-inclusive)"



        So if you do len(a[2:2]) the output is 0.






        share|improve this answer
























          0












          0








          0






          You have to specify the range you want to look at.



          len(a[1:2]) should do the trick.



          len(a[x:y]) simply means "the length of a from element x to y (non-inclusive)"



          So if you do len(a[2:2]) the output is 0.






          share|improve this answer












          You have to specify the range you want to look at.



          len(a[1:2]) should do the trick.



          len(a[x:y]) simply means "the length of a from element x to y (non-inclusive)"



          So if you do len(a[2:2]) the output is 0.







          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered Nov 23 '18 at 1:16









          bunbun

          2,03532446




          2,03532446























              0














              You can use:



              print(len(a[2:3]))


              Or if want it builtin, do a function:



              _len=len
              
def len(l):
              
    if _len(l)==0:
              
        return 0
              
    elif isinstance(l[0],list):
              
        return _len(l)
              
    return _len([l])
              

              
a=[[1,1,1],[1,1,1],[1,1,1]]
              
print(len(a[2]))


              Both Output:



              1





              share|improve this answer


























                0














                You can use:



                print(len(a[2:3]))


                Or if want it builtin, do a function:



                _len=len
                
def len(l):
                
    if _len(l)==0:
                
        return 0
                
    elif isinstance(l[0],list):
                
        return _len(l)
                
    return _len([l])
                

                
a=[[1,1,1],[1,1,1],[1,1,1]]
                
print(len(a[2]))


                Both Output:



                1





                share|improve this answer
























                  0












                  0








                  0






                  You can use:



                  print(len(a[2:3]))


                  Or if want it builtin, do a function:



                  _len=len
                  
def len(l):
                  
    if _len(l)==0:
                  
        return 0
                  
    elif isinstance(l[0],list):
                  
        return _len(l)
                  
    return _len([l])
                  

                  
a=[[1,1,1],[1,1,1],[1,1,1]]
                  
print(len(a[2]))


                  Both Output:



                  1





                  share|improve this answer












                  You can use:



                  print(len(a[2:3]))


                  Or if want it builtin, do a function:



                  _len=len
                  
def len(l):
                  
    if _len(l)==0:
                  
        return 0
                  
    elif isinstance(l[0],list):
                  
        return _len(l)
                  
    return _len([l])
                  

                  
a=[[1,1,1],[1,1,1],[1,1,1]]
                  
print(len(a[2]))


                  Both Output:



                  1






                  share|improve this answer












                  share|improve this answer



                  share|improve this answer










                  answered Nov 23 '18 at 1:17









                  U9-Forward

                  13.1k21137




                  13.1k21137






























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