How to sort multidimensional array by column

Question

Is there a way to use the sort   method or any other method to sort a list by column  Lets say I have the list      John 2    Jim 9    Jason 1      And I wanted to sort it so that it would look like this      Jason 1    John 2    Jim 9       What would be the best approach to do this   Edit   Right now I am running into an index out of range error  I have a 2 dimensional array that is lets say 1000 rows b 3 columns  I want to sort it based on the third column  Is this the right code for that    sorted list   sorted list not sorted  key lambda x x 2

User · Answer

You can use list sort with its optional key parameter and a lambda expression    gt  gt  gt  lst               John  2             Jim  9             Jason  1         gt  gt  gt  lst sort key lambda x x 1    gt  gt  gt  lst    Jason   1     John   2     Jim   9    gt  gt  gt    This will sort the list in-place     Note that for large lists  it will be faster to use operator itemgetter instead of a lambda    gt  gt  gt  from operator import itemgetter  gt  gt  gt  lst               John  2             Jim  9             Jason  1         gt  gt  gt  lst sort key itemgetter 1    gt  gt  gt  lst    Jason   1     John   2     Jim   9    gt  gt  gt

User · Answer

below solution worked for me in case of required number is float  Solution  table sorted table key lambda x  float x 5    for row in table         Ntable add row row

User · Answer

The optional key parameter to sort sorted is a function  The function is called for each item and the return values determine the ordering of the sort   gt  gt  gt  lst      John   2     Jim   9     Jason   1    gt  gt  gt  def my key func item           print  The key for    is     format item  item 1            return item 1        gt  gt  gt  sorted lst  key my key func  The key for   John   2  is 2 The key for   Jim   9  is 9 The key for   Jason   1  is 1    Jason   1     John   2     Jim   9     taking the print out of the function leaves   gt  gt  gt  def my key func item           return item 1    This function is simple enough to write  inline  as a lambda function   gt  gt  gt  sorted lst  key lambda item  item 1      Jason   1     John   2     Jim   9

User · Answer

You can use the sorted method with a key   sorted a  key lambda x   x 1

User · Answer

Yes   The sorted built-in accepts a key argument   sorted li key lambda x  x 1   Out 31      Jason   1     John   2     Jim   9     note that sorted returns a new list   If you want to sort in-place  use the  sort method of your list  which also  conveniently  accepts a key argument    or alternatively   from operator import itemgetter sorted li key itemgetter 1   Out 33      Jason   1     John   2     Jim   9     Read more on the python wiki

User · Answer

sorted list  key lambda x  x 1     Note  this works on time variable too

[python] How to sort multidimensional array by column?

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