Getting key with maximum value in dictionary

Question

I have a dictionary  keys are strings  values are integers   Example    stats     a  1000   b  3000   c   100    I d like to get  b  as an answer  since it s the key with a higher value   I did the following  using an intermediate list with reversed key-value tuples   inverse     value  key  for key  value in stats items    print max inverse  1    Is that one the better  or even more elegant  approach

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Here is another one   stats     a  1000   b  3000   c   100  max stats iterkeys    key lambda k  stats k     The function key simply returns the value that should be used for ranking and max   returns the demanded element right away

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I was not satisfied with any of these answers  max always picks the first key with the max value  The dictionary could have multiple keys with that value   def keys with top values my dict       return  key  for  key  value  in my dict items   if value    max my dict values       Posting this answer in case it helps someone out  See the below SO post  Which maximum does Python pick in the case of a tie

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You can use operator itemgetter for that   import operator stats     a  1000   b  3000   c   100  max stats iteritems    key operator itemgetter 1   0    And instead of building a new list in memory use stats iteritems    The key parameter to the max   function is a function that computes a key that is used to determine how to rank items   Please note that if you were to have another key-value pair  d   3000 that this method will only return one of the two even though they both have the maximum value     gt  gt  gt  import operator  gt  gt  gt  stats     a  1000   b  3000   c   100   d  3000   gt  gt  gt  max stats iteritems    key operator itemgetter 1   0   b     If using Python3    gt  gt  gt  max stats items    key operator itemgetter 1   0   b

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Much simpler to understand approach   dict      a  302   e  53   g  302   h  100   max value keys    key for key in dict keys   if dict key     max dict values     print max value keys    prints a list of keys with max value   Output    a    g    Now you can choose only one key   maximum   dict max value keys 0

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For scientific python users  here is a simple solution using Pandas   import pandas as pd stats     a   1000   b   3000   c   100  series   pd Series stats  series idxmax     gt  gt  gt  b

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max stats  key stats get  if stats else None stats can be an empty dictionary as well and max stats  key stats get  will break in that situation

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In the case you have more than one key with the same value  for example   stats     a  1000   b  3000   c   100   d  3000   e  3000    You could get a collection with all the keys with max value as follow   from collections import defaultdict from collections import OrderedDict  groupedByValue   defaultdict list  for key  value in sorted stats items         groupedByValue value  append key      1000    a    3000    b    d    e    100    c     groupedByValue max groupedByValue       b    d    e

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A heap queue is a generalised solution which allows you to extract the top n keys ordered by value   from heapq import nlargest  stats     a  1000   b  3000   c   100   res1   nlargest 1  stats  key stats   getitem         b   res2   nlargest 2  stats  key stats   getitem         b    a    res1 val   next iter res1                            b    Note dict   getitem   is the method called by the syntactic sugar dict    As opposed to dict get  it will return KeyError if a key is not found  which here cannot occur

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A heap queue is a generalised solution which allows you to extract the top n keys ordered by value   from heapq import nlargest  stats     a  1000   b  3000   c   100   res1   nlargest 1  stats  key stats   getitem         b   res2   nlargest 2  stats  key stats   getitem         b    a    res1 val   next iter res1                            b    Note dict   getitem   is the method called by the syntactic sugar dict    As opposed to dict get  it will return KeyError if a key is not found  which here cannot occur

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Here is another one   stats     a  1000   b  3000   c   100  max stats iterkeys    key lambda k  stats k     The function key simply returns the value that should be used for ranking and max   returns the demanded element right away

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d     A   4  B  10   min v   min zip d values    d keys       min v is  4  A    max v   max zip d values    d keys       max v is  10  B

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1 to  Aric Coady s simplest solution   And also one way to random select one of keys with max value in the dictionary   stats     a  1000   b  3000   c   100   d  3000   import random maxV   max stats values      Choice is one of the keys with max value choice   random choice  key for key  value in stats items   if value    maxV

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You can use    max d  key   d get     which is equivalent to  max d  key   lambda k   d get k     To return the key  value pair use   max d items    key   lambda k   k 1

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max  value  key  for key  value in stats items    1

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In the case you have more than one key with the same value  for example   stats     a  1000   b  3000   c   100   d  3000   e  3000    You could get a collection with all the keys with max value as follow   from collections import defaultdict from collections import OrderedDict  groupedByValue   defaultdict list  for key  value in sorted stats items         groupedByValue value  append key      1000    a    3000    b    d    e    100    c     groupedByValue max groupedByValue       b    d    e

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I tested the accepted answer AND  thewolf s fastest solution against a very basic loop and the loop was faster than both   import time import operator   d     a  str i   i for i in range 1000000    def t1 dct       mx   float  -inf       key   None     for k v in dct items            if v  gt  mx              mx   v             key   k     return key  def t2 dct       v list dct values        k list dct keys        return k v index max v     def t3 dct       return max dct items   key operator itemgetter 1   0   start   time time   for i in range 25       m   t1 d  end   time time   print   Iterating    str end-start    start   time time   for i in range 25       m   t2 d  end   time time   print   List creating    str end-start    start   time time   for i in range 25       m   t3 d  end   time time   print   Accepted answer    str end-start     results   Iterating  3 8201940059661865 List creating  6 928712844848633 Accepted answer  5 464320182800293

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Example   stats     a  1000   b  3000   c   100    if you wanna find the max value with its key  maybe follwing could be simple  without any relevant functions   max stats  key stats get    the output is the key which has the max value

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If you need to know only a key with the max value you can do it without iterkeys or iteritems because iteration through dictionary in Python is iteration through it s keys  max key   max stats  key lambda k  stats k    EDIT  From comments   user1274878    I am new to python  Can you please explain your answer in steps   Yep    max  max iterable   key   max arg1  arg2   args   key   Return the largest item in an iterable or the largest of two or more arguments   The optional key argument describes how to compare elements to get maximum among them  lambda  lt item gt   return  lt a result of operation with item gt    Returned values will be compared  Dict Python dict is a hash table  A key of dict is a hash of an object declared as a key  Due to performance reasons iteration though a dict implemented as iteration through it s keys  Therefore we can use it to rid operation of obtaining a keys list  Closure  A function defined inside another function is called a nested function  Nested functions can access variables of the enclosing scope   The stats variable available through   closure   attribute of the lambda function as a pointer to the value of the variable defined in the parent scope

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I have tested MANY variants  and this is the fastest way to return the key of dict with the max value   def keywithmaxval d            a  create a list of the dict s keys and values            b  return the key with the max value           v list d values         k list d keys         return k v index max v      To give you an idea  here are some candidate methods   def f1           v list d1 values         k list d1 keys         return k v index max v     def f2        d3  v k for k v in d1 items        return d3 max d3    def f3        return list filter lambda t  t 1   max d1 values     d1 items     0  0       def f3b          same as f3 but remove the call to max from the lambda     m max d1 values        return list filter lambda t  t 1   m  d1 items     0  0           def f4        return  k for k v in d1 items   if v  max d1 values     0       def f4b          same as f4 but remove the max from the comprehension     m max d1 values        return  k for k v in d1 items   if v  m  0           def f5        return max d1 items    key operator itemgetter 1   0       def f6        return max d1 key d1 get        def f7             a  create a list of the dict s keys and values            b  return the key with the max value             v list d1 values         return list d1 keys    v index max v         def f8         return max d1  key lambda k  d1 k         tl  f1 f2  f3b  f4b  f5  f6  f7  f8  f4 f3       cmpthese cmpthese tl c 100     The test dictionary   d1  1  1  2  2  3  8  4  3  5  6  6  9  7  17  8  4  9  20  10  7  11  15       12  10  13  10  14  18  15  18  16  5  17  13  18  21  19  21  20  8       21  8  22  16  23  16  24  11  25  24  26  11  27  112  28  19  29  19       30  19  3077  36  32  6  33  27  34  14  35  14  36  22  4102  39  38  22       39  35  40  9  41  110  42  9  43  30  44  17  45  17  46  17  47  105  48  12       49  25  50  25  51  25  52  12  53  12  54  113  1079  50  56  20  57  33       58  20  59  33  60  20  61  20  62  108  63  108  64  7  65  28  66  28  67  28       68  15  69  15  70  15  71  103  72  23  73  116  74  23  75  15  76  23  77  23       78  36  79  36  80  10  81  23  82  111  83  111  84  10  85  10  86  31  87  31       88  18  89  31  90  18  91  93  92  18  93  18  94  106  95  106  96  13  9232  35       98  26  99  26  100  26  101  26  103  88  104  13  106  13  107  101  1132  63       2158  51  112  21  113  13  116  21  118  34  119  34  7288  45  121  96  122  21       124  109  125  109  128  8  1154  32  131  29  134  29  136  16  137  91  140  16       142  104  143  104  146  117  148  24  149  24  152  24  154  24  155  86  160  11       161  99  1186  76  3238  49  167  68  170  11  172  32  175  81  178  32  179  32       182  94  184  19  31  107  188  107  190  107  196  27  197  27  202  27  206  89       208  14  214  102  215  102  220  115  37  22  224  22  226  14  232  22  233  84       238  35  242  97  244  22  250  110  251  66  1276  58  256  9  2308  33  262  30       263  79  268  30  269  30  274  92  1300  27  280  17  283  61  286  105  292  118       296  25  298  25  304  25  310  87  1336  71  319  56  322  100  323  100  325  25       55  113  334  69  340  12  1367  40  350  82  358  33  364  95  376  108       377  64  2429  46  394  28  395  77  404  28  412  90  1438  53  425  59  430  103       1456  97  433  28  445  72  448  23  466  85  479  54  484  98  485  98  488  23       6154  37  502  67  4616  34  526  80  538  31  566  62  3644  44  577  31  97  119       592  26  593  75  1619  48  638  57  646  101  650  26  110  114  668  70  2734  41       700  83  1732  30  719  52  728  96  754  65  1780  74  4858  47  130  29  790  78       1822  43  2051  38  808  29  850  60  866  29  890  73  911  42  958  55  970  99       976  24  166  112    And the test results under Python 3 2       rate sec       f4      f3    f3b     f8     f5     f2    f4b     f6     f7     f1 f4       454       --   -2 5  -96 9  -97 5  -98 6  -98 6  -98 7  -98 7  -98 9  -99 0  f3       466     2 6       -- -96 8  -97 4  -98 6  -98 6  -98 6  -98 7  -98 9  -99 0  f3b   14 715  3138 9  3057 4      -- -18 6  -55 5  -56 0  -56 4  -58 3  -63 8  -68 4  f8    18 070  3877 3  3777 3   22 8      -- -45 4  -45 9  -46 5  -48 8  -55 5  -61 2  f5    33 091  7183 7  7000 5  124 9   83 1      --  -1 0   -2 0   -6 3  -18 6  -29 0  f2    33 423  7256 8  7071 8  127 1   85 0    1 0      --  -1 0   -5 3  -17 7  -28 3  f4b   33 762  7331 4  7144 6  129 4   86 8    2 0    1 0      --  -4 4  -16 9  -27 5  f6    35 300  7669 8  7474 4  139 9   95 4    6 7    5 6    4 6      -- -13 1  -24 2  f7    40 631  8843 2  8618 3  176 1  124 9   22 8   21 6   20 3   15 1      -- -12 8  f1    46 598 10156 7  9898 8  216 7  157 9   40 8   39 4   38 0   32 0   14 7      --   And under Python 2 7       rate sec       f3       f4     f8    f3b     f6     f5     f2    f4b     f7     f1 f3       384       --    -2 6  -97 1  -97 2  -97 9  -97 9  -98 0  -98 2  -98 5  -99 2  f4       394     2 6        -- -97 0  -97 2  -97 8  -97 9  -98 0  -98 1  -98 5  -99 1  f8    13 079  3303 3   3216 1      --  -5 6  -28 6  -29 9  -32 8  -38 3  -49 7  -71 2  f3b   13 852  3504 5   3412 1    5 9      -- -24 4  -25 8  -28 9  -34 6  -46 7  -69 5  f6    18 325  4668 4   4546 2   40 1   32 3      --  -1 8   -5 9  -13 5  -29 5  -59 6  f5    18 664  4756 5   4632 0   42 7   34 7    1 8      --  -4 1  -11 9  -28 2  -58 8  f2    19 470  4966 4   4836 5   48 9   40 6    6 2    4 3      --  -8 1  -25 1  -57 1  f4b   21 187  5413 0   5271 7   62 0   52 9   15 6   13 5    8 8      -- -18 5  -53 3  f7    26 002  6665 8   6492 4   98 8   87 7   41 9   39 3   33 5   22 7      -- -42 7  f1    45 354 11701 5  11399 0  246 8  227 4  147 5  143 0  132 9  114 1   74 4      --    You can see that f1 is the fastest under Python 3 2 and 2 7  or  more completely  keywithmaxval at the top of this post

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How about    max zip stats keys    stats values     key lambda t   t 1   0

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Much simpler to understand approach   dict      a  302   e  53   g  302   h  100   max value keys    key for key in dict keys   if dict key     max dict values     print max value keys    prints a list of keys with max value   Output    a    g    Now you can choose only one key   maximum   dict max value keys 0

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You can use operator itemgetter for that   import operator stats     a  1000   b  3000   c   100  max stats iteritems    key operator itemgetter 1   0    And instead of building a new list in memory use stats iteritems    The key parameter to the max   function is a function that computes a key that is used to determine how to rank items   Please note that if you were to have another key-value pair  d   3000 that this method will only return one of the two even though they both have the maximum value     gt  gt  gt  import operator  gt  gt  gt  stats     a  1000   b  3000   c   100   d  3000   gt  gt  gt  max stats iteritems    key operator itemgetter 1   0   b     If using Python3    gt  gt  gt  max stats items    key operator itemgetter 1   0   b

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I tested the accepted answer AND  thewolf s fastest solution against a very basic loop and the loop was faster than both   import time import operator   d     a  str i   i for i in range 1000000    def t1 dct       mx   float  -inf       key   None     for k v in dct items            if v  gt  mx              mx   v             key   k     return key  def t2 dct       v list dct values        k list dct keys        return k v index max v     def t3 dct       return max dct items   key operator itemgetter 1   0   start   time time   for i in range 25       m   t1 d  end   time time   print   Iterating    str end-start    start   time time   for i in range 25       m   t2 d  end   time time   print   List creating    str end-start    start   time time   for i in range 25       m   t3 d  end   time time   print   Accepted answer    str end-start     results   Iterating  3 8201940059661865 List creating  6 928712844848633 Accepted answer  5 464320182800293

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max stats  key stats get

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Counter   0 for word in stats keys        if stats word  gt  counter          Counter   stats  word  print Counter

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You can use operator itemgetter for that   import operator stats     a  1000   b  3000   c   100  max stats iteritems    key operator itemgetter 1   0    And instead of building a new list in memory use stats iteritems    The key parameter to the max   function is a function that computes a key that is used to determine how to rank items   Please note that if you were to have another key-value pair  d   3000 that this method will only return one of the two even though they both have the maximum value     gt  gt  gt  import operator  gt  gt  gt  stats     a  1000   b  3000   c   100   d  3000   gt  gt  gt  max stats iteritems    key operator itemgetter 1   0   b     If using Python3    gt  gt  gt  max stats items    key operator itemgetter 1   0   b

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Here is another one   stats     a  1000   b  3000   c   100  max stats iterkeys    key lambda k  stats k     The function key simply returns the value that should be used for ranking and max   returns the demanded element right away

User · Answer

Here is another one   stats     a  1000   b  3000   c   100  max stats iterkeys    key lambda k  stats k     The function key simply returns the value that should be used for ranking and max   returns the demanded element right away

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Per the iterated solutions via comments in the selected answer      In Python 3   max stats keys    key  lambda k  stats k      In Python 2   max stats iterkeys    key  lambda k  stats k

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max stats  key stats get

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You can use    max d  key   d get     which is equivalent to  max d  key   lambda k   d get k     To return the key  value pair use   max d items    key   lambda k   k 1

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max stats  key stats get  if stats else None stats can be an empty dictionary as well and max stats  key stats get  will break in that situation

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Given that more than one entry my have the max value  I would make a list of the keys that have the max value as their value    gt  gt  gt  stats     a  1000   b  3000   c   100   d  3000   gt  gt  gt   key for m in  max stats values     for key val in stats iteritems   if val    m    b    d     This will give you  b  and any other max key as well   Note  For python 3 use stats items   instead of stats iteritems

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I got here looking for how to return mydict keys   based on the value of mydict values    Instead of just the one key returned  I was looking to return the top x number of values   This solution is simpler than using the max   function and you can easily change the number of values returned   stats     a  1000   b  3000   c   100   x   sorted stats  key  lambda key stats key    reverse True    b    a    c     If you want the single highest ranking key  just use the index   x 0    b     If you want the top two highest ranking keys  just use list slicing   x  2    b    a

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1 to  Aric Coady s simplest solution   And also one way to random select one of keys with max value in the dictionary   stats     a  1000   b  3000   c   100   d  3000   import random maxV   max stats values      Choice is one of the keys with max value choice   random choice  key for key  value in stats items   if value    maxV

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With collections Counter you could do   gt  gt  gt  import collections  gt  gt  gt  stats     a  1000   b  3000   c   100   gt  gt  gt  stats   collections Counter stats   gt  gt  gt  stats most common 1     b   3000     If appropriate  you could simply start with an empty collections Counter and add to it   gt  gt  gt  stats   collections Counter    gt  gt  gt  stats  a      1   etc

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If you need to know only a key with the max value you can do it without iterkeys or iteritems because iteration through dictionary in Python is iteration through it s keys  max key   max stats  key lambda k  stats k    EDIT  From comments   user1274878    I am new to python  Can you please explain your answer in steps   Yep    max  max iterable   key   max arg1  arg2   args   key   Return the largest item in an iterable or the largest of two or more arguments   The optional key argument describes how to compare elements to get maximum among them  lambda  lt item gt   return  lt a result of operation with item gt    Returned values will be compared  Dict Python dict is a hash table  A key of dict is a hash of an object declared as a key  Due to performance reasons iteration though a dict implemented as iteration through it s keys  Therefore we can use it to rid operation of obtaining a keys list  Closure  A function defined inside another function is called a nested function  Nested functions can access variables of the enclosing scope   The stats variable available through   closure   attribute of the lambda function as a pointer to the value of the variable defined in the parent scope

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Example   stats     a  1000   b  3000   c   100    if you wanna find the max value with its key  maybe follwing could be simple  without any relevant functions   max stats  key stats get    the output is the key which has the max value

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I have tested MANY variants  and this is the fastest way to return the key of dict with the max value   def keywithmaxval d            a  create a list of the dict s keys and values            b  return the key with the max value           v list d values         k list d keys         return k v index max v      To give you an idea  here are some candidate methods   def f1           v list d1 values         k list d1 keys         return k v index max v     def f2        d3  v k for k v in d1 items        return d3 max d3    def f3        return list filter lambda t  t 1   max d1 values     d1 items     0  0       def f3b          same as f3 but remove the call to max from the lambda     m max d1 values        return list filter lambda t  t 1   m  d1 items     0  0           def f4        return  k for k v in d1 items   if v  max d1 values     0       def f4b          same as f4 but remove the max from the comprehension     m max d1 values        return  k for k v in d1 items   if v  m  0           def f5        return max d1 items    key operator itemgetter 1   0       def f6        return max d1 key d1 get        def f7             a  create a list of the dict s keys and values            b  return the key with the max value             v list d1 values         return list d1 keys    v index max v         def f8         return max d1  key lambda k  d1 k         tl  f1 f2  f3b  f4b  f5  f6  f7  f8  f4 f3       cmpthese cmpthese tl c 100     The test dictionary   d1  1  1  2  2  3  8  4  3  5  6  6  9  7  17  8  4  9  20  10  7  11  15       12  10  13  10  14  18  15  18  16  5  17  13  18  21  19  21  20  8       21  8  22  16  23  16  24  11  25  24  26  11  27  112  28  19  29  19       30  19  3077  36  32  6  33  27  34  14  35  14  36  22  4102  39  38  22       39  35  40  9  41  110  42  9  43  30  44  17  45  17  46  17  47  105  48  12       49  25  50  25  51  25  52  12  53  12  54  113  1079  50  56  20  57  33       58  20  59  33  60  20  61  20  62  108  63  108  64  7  65  28  66  28  67  28       68  15  69  15  70  15  71  103  72  23  73  116  74  23  75  15  76  23  77  23       78  36  79  36  80  10  81  23  82  111  83  111  84  10  85  10  86  31  87  31       88  18  89  31  90  18  91  93  92  18  93  18  94  106  95  106  96  13  9232  35       98  26  99  26  100  26  101  26  103  88  104  13  106  13  107  101  1132  63       2158  51  112  21  113  13  116  21  118  34  119  34  7288  45  121  96  122  21       124  109  125  109  128  8  1154  32  131  29  134  29  136  16  137  91  140  16       142  104  143  104  146  117  148  24  149  24  152  24  154  24  155  86  160  11       161  99  1186  76  3238  49  167  68  170  11  172  32  175  81  178  32  179  32       182  94  184  19  31  107  188  107  190  107  196  27  197  27  202  27  206  89       208  14  214  102  215  102  220  115  37  22  224  22  226  14  232  22  233  84       238  35  242  97  244  22  250  110  251  66  1276  58  256  9  2308  33  262  30       263  79  268  30  269  30  274  92  1300  27  280  17  283  61  286  105  292  118       296  25  298  25  304  25  310  87  1336  71  319  56  322  100  323  100  325  25       55  113  334  69  340  12  1367  40  350  82  358  33  364  95  376  108       377  64  2429  46  394  28  395  77  404  28  412  90  1438  53  425  59  430  103       1456  97  433  28  445  72  448  23  466  85  479  54  484  98  485  98  488  23       6154  37  502  67  4616  34  526  80  538  31  566  62  3644  44  577  31  97  119       592  26  593  75  1619  48  638  57  646  101  650  26  110  114  668  70  2734  41       700  83  1732  30  719  52  728  96  754  65  1780  74  4858  47  130  29  790  78       1822  43  2051  38  808  29  850  60  866  29  890  73  911  42  958  55  970  99       976  24  166  112    And the test results under Python 3 2       rate sec       f4      f3    f3b     f8     f5     f2    f4b     f6     f7     f1 f4       454       --   -2 5  -96 9  -97 5  -98 6  -98 6  -98 7  -98 7  -98 9  -99 0  f3       466     2 6       -- -96 8  -97 4  -98 6  -98 6  -98 6  -98 7  -98 9  -99 0  f3b   14 715  3138 9  3057 4      -- -18 6  -55 5  -56 0  -56 4  -58 3  -63 8  -68 4  f8    18 070  3877 3  3777 3   22 8      -- -45 4  -45 9  -46 5  -48 8  -55 5  -61 2  f5    33 091  7183 7  7000 5  124 9   83 1      --  -1 0   -2 0   -6 3  -18 6  -29 0  f2    33 423  7256 8  7071 8  127 1   85 0    1 0      --  -1 0   -5 3  -17 7  -28 3  f4b   33 762  7331 4  7144 6  129 4   86 8    2 0    1 0      --  -4 4  -16 9  -27 5  f6    35 300  7669 8  7474 4  139 9   95 4    6 7    5 6    4 6      -- -13 1  -24 2  f7    40 631  8843 2  8618 3  176 1  124 9   22 8   21 6   20 3   15 1      -- -12 8  f1    46 598 10156 7  9898 8  216 7  157 9   40 8   39 4   38 0   32 0   14 7      --   And under Python 2 7       rate sec       f3       f4     f8    f3b     f6     f5     f2    f4b     f7     f1 f3       384       --    -2 6  -97 1  -97 2  -97 9  -97 9  -98 0  -98 2  -98 5  -99 2  f4       394     2 6        -- -97 0  -97 2  -97 8  -97 9  -98 0  -98 1  -98 5  -99 1  f8    13 079  3303 3   3216 1      --  -5 6  -28 6  -29 9  -32 8  -38 3  -49 7  -71 2  f3b   13 852  3504 5   3412 1    5 9      -- -24 4  -25 8  -28 9  -34 6  -46 7  -69 5  f6    18 325  4668 4   4546 2   40 1   32 3      --  -1 8   -5 9  -13 5  -29 5  -59 6  f5    18 664  4756 5   4632 0   42 7   34 7    1 8      --  -4 1  -11 9  -28 2  -58 8  f2    19 470  4966 4   4836 5   48 9   40 6    6 2    4 3      --  -8 1  -25 1  -57 1  f4b   21 187  5413 0   5271 7   62 0   52 9   15 6   13 5    8 8      -- -18 5  -53 3  f7    26 002  6665 8   6492 4   98 8   87 7   41 9   39 3   33 5   22 7      -- -42 7  f1    45 354 11701 5  11399 0  246 8  227 4  147 5  143 0  132 9  114 1   74 4      --    You can see that f1 is the fastest under Python 3 2 and 2 7  or  more completely  keywithmaxval at the top of this post

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max stats  key stats get

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max  value  key  for key  value in stats items    1

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I was not satisfied with any of these answers  max always picks the first key with the max value  The dictionary could have multiple keys with that value   def keys with top values my dict       return  key  for  key  value  in my dict items   if value    max my dict values       Posting this answer in case it helps someone out  See the below SO post  Which maximum does Python pick in the case of a tie

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Per the iterated solutions via comments in the selected answer      In Python 3   max stats keys    key  lambda k  stats k      In Python 2   max stats iterkeys    key  lambda k  stats k

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key  value   max stats iteritems    key lambda x x 1     If you don t care about value  I d be surprised  but  you can do   key      max stats iteritems    key lambda x x 1     I like the tuple unpacking better than a  0  subscript at the end of the expression  I never like the readability of lambda expressions very much  but find this one better than the operator itemgetter 1  IMHO

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key  value   max stats iteritems    key lambda x x 1     If you don t care about value  I d be surprised  but  you can do   key      max stats iteritems    key lambda x x 1     I like the tuple unpacking better than a  0  subscript at the end of the expression  I never like the readability of lambda expressions very much  but find this one better than the operator itemgetter 1  IMHO

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Given that more than one entry my have the max value  I would make a list of the keys that have the max value as their value    gt  gt  gt  stats     a  1000   b  3000   c   100   d  3000   gt  gt  gt   key for m in  max stats values     for key val in stats iteritems   if val    m    b    d     This will give you  b  and any other max key as well   Note  For python 3 use stats items   instead of stats iteritems

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To get the maximum key value of the dictionary stats   stats     a  1000   b  3000   c   100     Based on keys    gt  gt  gt  max stats items    key   lambda x  x 0     c   100    Based on values    gt  gt  gt  max stats items    key   lambda x  x 1     b   3000   Of course  if you want to get only the key or value from the result  you can use tuple indexing  For Example  to get the key corresponding to the maximum value    gt  gt  gt  max stats items    key   lambda x  x 1   0   b   Explanation  The dictionary method items   in Python 3 returns a view object of the dictionary  When this view object is iterated over  by the max function  it yields the dictionary items as tuples of the form  key  value     gt  gt  gt  list stats items       c   100     b   3000     a   1000    When you use the lambda expression lambda x  x 1   in each iteration  x  is one of these tuples  key  value   So  by choosing the right index  you select whether you want to compare by keys or by values   Python 2  For Python 2 2  releases  the same code will work  However  it is better to use iteritems   dictionary method instead of items   for performance   Notes   This answer is based on the comments on Climbs lika Spyder s answer  The used code was tested on Python 3 5 2 and Python 2 7 10

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key  value   max stats iteritems    key lambda x x 1     If you don t care about value  I d be surprised  but  you can do   key      max stats iteritems    key lambda x x 1     I like the tuple unpacking better than a  0  subscript at the end of the expression  I never like the readability of lambda expressions very much  but find this one better than the operator itemgetter 1  IMHO

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With collections Counter you could do   gt  gt  gt  import collections  gt  gt  gt  stats     a  1000   b  3000   c   100   gt  gt  gt  stats   collections Counter stats   gt  gt  gt  stats most common 1     b   3000     If appropriate  you could simply start with an empty collections Counter and add to it   gt  gt  gt  stats   collections Counter    gt  gt  gt  stats  a      1   etc

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For scientific python users  here is a simple solution using Pandas   import pandas as pd stats     a   1000   b   3000   c   100  series   pd Series stats  series idxmax     gt  gt  gt  b

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I got here looking for how to return mydict keys   based on the value of mydict values    Instead of just the one key returned  I was looking to return the top x number of values   This solution is simpler than using the max   function and you can easily change the number of values returned   stats     a  1000   b  3000   c   100   x   sorted stats  key  lambda key stats key    reverse True    b    a    c     If you want the single highest ranking key  just use the index   x 0    b     If you want the top two highest ranking keys  just use list slicing   x  2    b    a

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To get the maximum key value of the dictionary stats   stats     a  1000   b  3000   c   100     Based on keys    gt  gt  gt  max stats items    key   lambda x  x 0     c   100    Based on values    gt  gt  gt  max stats items    key   lambda x  x 1     b   3000   Of course  if you want to get only the key or value from the result  you can use tuple indexing  For Example  to get the key corresponding to the maximum value    gt  gt  gt  max stats items    key   lambda x  x 1   0   b   Explanation  The dictionary method items   in Python 3 returns a view object of the dictionary  When this view object is iterated over  by the max function  it yields the dictionary items as tuples of the form  key  value     gt  gt  gt  list stats items       c   100     b   3000     a   1000    When you use the lambda expression lambda x  x 1   in each iteration  x  is one of these tuples  key  value   So  by choosing the right index  you select whether you want to compare by keys or by values   Python 2  For Python 2 2  releases  the same code will work  However  it is better to use iteritems   dictionary method instead of items   for performance   Notes   This answer is based on the comments on Climbs lika Spyder s answer  The used code was tested on Python 3 5 2 and Python 2 7 10

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max stats  key stats get

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Counter   0 for word in stats keys        if stats word  gt  counter          Counter   stats  word  print Counter

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You can use operator itemgetter for that   import operator stats     a  1000   b  3000   c   100  max stats iteritems    key operator itemgetter 1   0    And instead of building a new list in memory use stats iteritems    The key parameter to the max   function is a function that computes a key that is used to determine how to rank items   Please note that if you were to have another key-value pair  d   3000 that this method will only return one of the two even though they both have the maximum value     gt  gt  gt  import operator  gt  gt  gt  stats     a  1000   b  3000   c   100   d  3000   gt  gt  gt  max stats iteritems    key operator itemgetter 1   0   b     If using Python3    gt  gt  gt  max stats items    key operator itemgetter 1   0   b

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key  value   max stats iteritems    key lambda x x 1     If you don t care about value  I d be surprised  but  you can do   key      max stats iteritems    key lambda x x 1     I like the tuple unpacking better than a  0  subscript at the end of the expression  I never like the readability of lambda expressions very much  but find this one better than the operator itemgetter 1  IMHO

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How about    max zip stats keys    stats values     key lambda t   t 1   0

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d     A   4  B  10   min v   min zip d values    d keys       min v is  4  A    max v   max zip d values    d keys       max v is  10  B

[python] Getting key with maximum value in dictionary?

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