Flatten list of lists

Question

I m having a problem with square brackets in Python  I wrote a code that produces the following output     180 0    173 8    164 2    156 5    147 2    138 2     But I would like to perform some calculations with that  but the the square brackets won t let me   How can I remove the brackets  I saw some examples to do that but I could not apply them to this case

User · Answer

gt  gt  gt  lis   180 0    173 8    164 2    156 5    147 2    138 2    gt  gt  gt   x 0  for x in lis   180 0  173 8  164 2  156 5  147 2  138 2

User · Answer

Flatten the list to  remove the brackets  using a nested list comprehension  This will un-nest each list stored in your list of lists   list of lists     180 0    173 8    164 2    156 5    147 2    138 2   flattened    val for sublist in list of lists for val in sublist    Nested list comprehensions evaluate in the same manner that they unwrap  i e  add newline and tab for each new loop  So in this case   flattened    val for sublist in list of lists for val in sublist    is equivalent to   flattened      for sublist in list of lists      for val in sublist          flattened append val    The big difference is that the list comp evaluates MUCH faster than the unraveled loop and eliminates the append calls    If you have multiple items in a sublist the list comp will even flatten that  ie   gt  gt  gt  list of lists     180 0  1  2  3    173 8    164 2    156 5    147 2    138 2    gt  gt  gt  flattened     val for sublist in list of lists for val in sublist   gt  gt  gt  flattened   180 0  1  2  3  173 8  164 2  156 5  147 2 138 2

User · Answer

I would use itertools chain - this will also cater for   1 element in each sublist   from itertools import chain list chain from iterable   180 0    173 8    164 2    156 5    147 2    138 2

User · Answer

Given  d     180 0    173 8    164 2    156 5    147 2    138 2     and your specific question  How can I remove the brackets    Using list comprehension    new d    i 0  for i in d    will give you this   180 0  173 8  164 2  156 5  147 2  138 2    then you can access individual items with the appropriate index  e g   new d 0  will give you 180 0 etc which you can then use for math   If you are going to have a collection of data  you will have some sort of bracket or parenthesis   Note  this solution is aimed specifically at your question problem  it doesn t provide a generalized solution  I e   it will work for your case

[python] Flatten list of lists

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