How do I count unique values inside a list

Question

So I m trying to make this program that will ask the user for input and store the values in an array   list  Then when a blank line is entered it will tell the user how many of those values are unique  I m building this for real life reasons and not as a problem set   enter  happy enter  rofl enter  happy enter  mpg8 enter  Cpp enter  Cpp enter  There are 4 unique words    My code is as follows     ask for input ipta   raw input  Word        create list  uniquewords       counter   0 uniquewords append ipta   a   0     loop thingy   while loop to ask for input and append in list while ipta     ipta   raw input  Word       new words append input1    counter   counter   1  for p in uniquewords      and that s about all I ve gotten so far  I m not sure how to count the unique number of words in a list  If someone can post the solution so I can learn from it  or at least show me how it would be great  thanks

User · Answer

aa  XXYYYSBAA  bb dict zip list aa   list aa  count i  for i in list aa     print bb    output      X   2   Y   3   S   1   B   1   A   2

User · Answer

You can use a set to remove duplicates  and then the len function to count the elements in the set   len set new words

User · Answer

The following should work  The lambda function filter out the duplicated words   inputs    input   raw input  Word     strip   while input      inputs append input      input   raw input  Word     strip   uniques reduce lambda x y    y in x  and x  or x  y   inputs      print  There are   len uniques    unique words

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For ndarray there is a numpy method called unique   np unique array name    Examples    gt  gt  gt  np unique  1  1  2  2  3  3   array  1  2  3    gt  gt  gt  a   np array   1  1    2  3     gt  gt  gt  np unique a  array  1  2  3     For a Series there is a function call value counts     Series name value counts

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Although a set is the easiest way  you could also use a dict and use some dict has key  to populate a dictionary with only unique keys and values   Assuming you have already populated words   with input from the user  create a dict mapping the unique words in the list to a number   word map      i   1 for j in range len words        if not word map has key words j            word map words j     i         i    1                                                              num unique words   len new map    or num unique words   i  however you prefer

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If you would like to have a histogram of unique values here s oneliner import numpy as np     unique labels  unique counts   np unique labels list  return counts True  labels histogram   dict zip unique labels  unique counts

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Other method by using pandas  import pandas as pd  LIST     a   a   c   a   a   v   d   counts values   pd Series LIST  value counts   values  pd Series LIST  value counts   index df results   pd DataFrame list zip values counts   columns   value   count      You can then export results in any format you want

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In addition  use collections Counter to refactor your code    from collections import Counter  words     a    b    c    a    Counter words  keys     equals to list set words   Counter words  values     counts the elements  frequency   Output     a    c    b    2  1  1

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ipta   raw input  Word        asks for input words         creates list  while ipta     while loop to ask for input and append in list   words append ipta    ipta   raw input  Word       words append ipta   Create a set  sets do not have repeats unique words   set words   print  There are      str len unique words       unique words

User · Answer

Use a set   words     a    b    c    a   unique words   set words                   set   a    b    c    unique word count   len unique words       3   Armed with this  your solution could be as simple as   words      ipta   raw input  Word      while ipta    words append ipta    ipta   raw input  Word      unique word count   len set words    print  There are  d unique words     unique word count

User · Answer

How about  import pandas as pd  List with all words words      Code for adding words words append  test      When Input equals blank  pd Series words  nunique    It returns how many unique values are in a list

User · Answer

I d use a set myself  but here s yet another way   uniquewords      while True      ipta   raw input  Word         if ipta                break     if not ipta in uniquewords          uniquewords append ipta  print  There are   len uniquewords    unique words

User · Answer

values  counts   np unique words  return counts True

User · Answer

ipta   raw input  Word        asks for input words         creates list unique words   set words

[python] How do I count unique values inside a list

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