Python For each list element apply a function across the list

Question

Given  1 2 3 4 5   how can I do something like   1 1  1 2  1 3 1 4 1 5        3 1 3 2 3 3 3 4 3 5      5 1 5 2 5 3 5 4 5 5   I would like to store all the results  find the minimum  and return the two numbers used to find the minimum  So in the case I ve described above I would like to return  1 5    So basically I would like to do something like  for each element i in the list map some function across all elements in the list  taking i and j as parameters store the result in a master list  find the minimum value in the master list  and return the arguments i  jused to calculate this minimum value   In my real problem I have a list objects coordinates  and the function I am using takes two coordinates and calculates the euclidean distance  I m trying to find minimum euclidean distance between any two points but I don t need a fancy algorithm

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If you don t mind importing the numpy package  it has a lot of convenient functionality built in   It s likely to be much more efficient to use their data structures than lists of lists  etc   from   future   import division  import numpy  data   numpy asarray  1 2 3 4 5   dists   data reshape  1 5     data reshape  5 1    print dists  which   dists argmin    r c     which    5  which   5    assumes C ordering    pick whichever is most appropriate for you    minval   dists r c  minval   dists min   minval   dists ravel   which

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Some readable python   def JoeCalimar l       masterList          for i in l          for j in l              masterList append 1  i j      pos   masterList index min masterList       a   pos len masterList      b   pos len masterList      return  l a  l b     Let me know if something is not clear

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If I m correct in thinking that you want to find the minimum value of a function for all possible pairs of 2 elements from a list     l    1 2 3 4 5   def f i j      return i j     Prints min value of f i j  along with i and j print min   f i j  i j  for i in l for j in l

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If working with Python  2 6  including 3 x   you can   from   future   import division import operator  itertools  def getmin alist       return min           operator div  pair   pair          for pair in itertools product alist  repeat 2        1   getmin  1  2  3  4  5     EDIT  Now that I think of it and if I remember my mathematics correctly  this should also give the answer assuming that all numbers are non-negative   def getmin alist       return min alist   max alist

User · Answer

If you don t mind importing the numpy package  it has a lot of convenient functionality built in   It s likely to be much more efficient to use their data structures than lists of lists  etc   from   future   import division  import numpy  data   numpy asarray  1 2 3 4 5   dists   data reshape  1 5     data reshape  5 1    print dists  which   dists argmin    r c     which    5  which   5    assumes C ordering    pick whichever is most appropriate for you    minval   dists r c  minval   dists min   minval   dists ravel   which

User · Answer

If you don t mind importing the numpy package  it has a lot of convenient functionality built in   It s likely to be much more efficient to use their data structures than lists of lists  etc   from   future   import division  import numpy  data   numpy asarray  1 2 3 4 5   dists   data reshape  1 5     data reshape  5 1    print dists  which   dists argmin    r c     which    5  which   5    assumes C ordering    pick whichever is most appropriate for you    minval   dists r c  minval   dists min   minval   dists ravel   which

User · Answer

Some readable python   def JoeCalimar l       masterList          for i in l          for j in l              masterList append 1  i j      pos   masterList index min masterList       a   pos len masterList      b   pos len masterList      return  l a  l b     Let me know if something is not clear

User · Answer

Doing it the mathy way     nums    1  2  3  4  5  min combo    min nums   max nums     Unless  of course  you have negatives in there   In that case  this won t work because you actually want the min and max absolute values - the numerator should be close to zero  and the denominator far from it  in either direction   And double negatives would break it

User · Answer

Doing it the mathy way     nums    1  2  3  4  5  min combo    min nums   max nums     Unless  of course  you have negatives in there   In that case  this won t work because you actually want the min and max absolute values - the numerator should be close to zero  and the denominator far from it  in either direction   And double negatives would break it

User · Answer

If I m correct in thinking that you want to find the minimum value of a function for all possible pairs of 2 elements from a list     l    1 2 3 4 5   def f i j      return i j     Prints min value of f i j  along with i and j print min   f i j  i j  for i in l for j in l

User · Answer

You can do this using list comprehensions and min    Python 3 0 code     gt  gt  gt  nums    1 2 3 4 5   gt  gt  gt    x y  for x in nums for y in nums    1  1    1  2    1  3    1  4    1  5    2  1    2  2    2  3    2  4    2  5    3  1    3  2    3  3    3  4    3  5    4  1    4  2    4  3    4  4    4  5    5  1    5  2    5  3    5  4    5  5    gt  gt  gt  min    key lambda pair  pair 0  pair 1    1  5    Note that to run this on Python 2 5 you ll need to either make one of the arguments a float  or do from   future   import division so that 1 5 correctly equals 0 2 instead of 0

User · Answer

You can do this using list comprehensions and min    Python 3 0 code     gt  gt  gt  nums    1 2 3 4 5   gt  gt  gt    x y  for x in nums for y in nums    1  1    1  2    1  3    1  4    1  5    2  1    2  2    2  3    2  4    2  5    3  1    3  2    3  3    3  4    3  5    4  1    4  2    4  3    4  4    4  5    5  1    5  2    5  3    5  4    5  5    gt  gt  gt  min    key lambda pair  pair 0  pair 1    1  5    Note that to run this on Python 2 5 you ll need to either make one of the arguments a float  or do from   future   import division so that 1 5 correctly equals 0 2 instead of 0

User · Answer

You can do this using list comprehensions and min    Python 3 0 code     gt  gt  gt  nums    1 2 3 4 5   gt  gt  gt    x y  for x in nums for y in nums    1  1    1  2    1  3    1  4    1  5    2  1    2  2    2  3    2  4    2  5    3  1    3  2    3  3    3  4    3  5    4  1    4  2    4  3    4  4    4  5    5  1    5  2    5  3    5  4    5  5    gt  gt  gt  min    key lambda pair  pair 0  pair 1    1  5    Note that to run this on Python 2 5 you ll need to either make one of the arguments a float  or do from   future   import division so that 1 5 correctly equals 0 2 instead of 0

User · Answer

gt  gt  gt  nums    1  2  3  4  5       gt  gt  gt  min map  lambda t    float t 0   t 1    t      x  y  for x in nums for y in nums    1   1  5

User · Answer

If I m correct in thinking that you want to find the minimum value of a function for all possible pairs of 2 elements from a list     l    1 2 3 4 5   def f i j      return i j     Prints min value of f i j  along with i and j print min   f i j  i j  for i in l for j in l

User · Answer

If you don t mind importing the numpy package  it has a lot of convenient functionality built in   It s likely to be much more efficient to use their data structures than lists of lists  etc   from   future   import division  import numpy  data   numpy asarray  1 2 3 4 5   dists   data reshape  1 5     data reshape  5 1    print dists  which   dists argmin    r c     which    5  which   5    assumes C ordering    pick whichever is most appropriate for you    minval   dists r c  minval   dists min   minval   dists ravel   which

User · Answer

If working with Python  2 6  including 3 x   you can   from   future   import division import operator  itertools  def getmin alist       return min           operator div  pair   pair          for pair in itertools product alist  repeat 2        1   getmin  1  2  3  4  5     EDIT  Now that I think of it and if I remember my mathematics correctly  this should also give the answer assuming that all numbers are non-negative   def getmin alist       return min alist   max alist

User · Answer

If working with Python  2 6  including 3 x   you can   from   future   import division import operator  itertools  def getmin alist       return min           operator div  pair   pair          for pair in itertools product alist  repeat 2        1   getmin  1  2  3  4  5     EDIT  Now that I think of it and if I remember my mathematics correctly  this should also give the answer assuming that all numbers are non-negative   def getmin alist       return min alist   max alist

User · Answer

Some readable python   def JoeCalimar l       masterList          for i in l          for j in l              masterList append 1  i j      pos   masterList index min masterList       a   pos len masterList      b   pos len masterList      return  l a  l b     Let me know if something is not clear

User · Answer

Some readable python   def JoeCalimar l       masterList          for i in l          for j in l              masterList append 1  i j      pos   masterList index min masterList       a   pos len masterList      b   pos len masterList      return  l a  l b     Let me know if something is not clear

User · Answer

If working with Python  2 6  including 3 x   you can   from   future   import division import operator  itertools  def getmin alist       return min           operator div  pair   pair          for pair in itertools product alist  repeat 2        1   getmin  1  2  3  4  5     EDIT  Now that I think of it and if I remember my mathematics correctly  this should also give the answer assuming that all numbers are non-negative   def getmin alist       return min alist   max alist

User · Answer

You can do this using list comprehensions and min    Python 3 0 code     gt  gt  gt  nums    1 2 3 4 5   gt  gt  gt    x y  for x in nums for y in nums    1  1    1  2    1  3    1  4    1  5    2  1    2  2    2  3    2  4    2  5    3  1    3  2    3  3    3  4    3  5    4  1    4  2    4  3    4  4    4  5    5  1    5  2    5  3    5  4    5  5    gt  gt  gt  min    key lambda pair  pair 0  pair 1    1  5    Note that to run this on Python 2 5 you ll need to either make one of the arguments a float  or do from   future   import division so that 1 5 correctly equals 0 2 instead of 0

User · Answer

Doing it the mathy way     nums    1  2  3  4  5  min combo    min nums   max nums     Unless  of course  you have negatives in there   In that case  this won t work because you actually want the min and max absolute values - the numerator should be close to zero  and the denominator far from it  in either direction   And double negatives would break it

User · Answer

If I m correct in thinking that you want to find the minimum value of a function for all possible pairs of 2 elements from a list     l    1 2 3 4 5   def f i j      return i j     Prints min value of f i j  along with i and j print min   f i j  i j  for i in l for j in l

User · Answer

gt  gt  gt  nums    1  2  3  4  5       gt  gt  gt  min map  lambda t    float t 0   t 1    t      x  y  for x in nums for y in nums    1   1  5

User · Answer

Doing it the mathy way     nums    1  2  3  4  5  min combo    min nums   max nums     Unless  of course  you have negatives in there   In that case  this won t work because you actually want the min and max absolute values - the numerator should be close to zero  and the denominator far from it  in either direction   And double negatives would break it

[python] Python: For each list element apply a function across the list

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