List showing running total of instances

List showing running total of instances - Printable Version

+- Python Forum (https://python-forum.io)
+-- Forum: Python Coding (https://python-forum.io/forum-7.html)
+--- Forum: Homework (https://python-forum.io/forum-9.html)
+--- Thread: List showing running total of instances (/thread-1635.html)

Pages: 1 2

List showing running total of instances - Pie_Fun - Jan-17-2017

Hi Folks,

to try and explain what I'm trying to do
Say I have a list of numbers
48,52,55,48,52,55,60,62,48
what I want is a corresponding list with the number of instances that a number has appeared to that point in the list.
so it would be
1,1,1,2,2,2,1,1,3

Thanks for any feedback

RE: List showing running total of instances - micseydel - Jan-17-2017

What have you tried?

RE: List showing running total of instances - Pie_Fun - Jan-18-2017

ok i've got it sorted
if its of benefit to anybody else

from collections import Counter
AList = [1,2,1,2,3,2,1]
BList = []
CList = []
c = collections.Counter()
myDict = {}
count = 1
for x in AList:
BList.append(x)
for y in BList:
CList.append(y)
c.update(CList)
BList = []
myDict[count] = {'notecount':dict©}
count = count + 1
c = collections.Counter()

ps can't easily see how to to put the code into a format for the forum - so spacing is off and dict© is mangled as a copyright symbol

RE: List showing running total of instances - sparkz_alot - Jan-18-2017

(Jan-18-2017, 11:00 AM)Pie_Fun Wrote: ps can't easily see how to to put the code into a format for the forum - so spacing is off and dict© is mangled as a copyright symbol

Which makes it pretty much useless to anyone wishing to read or use your solution. Check the Help document at the top of the page.

RE: List showing running total of instances - Pie_Fun - Jan-18-2017

from collections import Counter           
aList = [1,2,1,2,3,2,1]
bList = []
cList = []
c = collections.Counter()
myDict = {}
count = 1
for x in aList:  
   bList.append(x)
   for y in bList:
       cList.append(y)
   c.update(finalList)
   bList = []
   myDict[count] = {'notecount':dict(c)}
   count = count + 1
   c = collections.Counter()

RE: List showing running total of instances - wavic - Jan-18-2017

You need to count an element in the incrementing slices of the first list and append the result for an element to the new list. You don't need 2 additional list neather a dict.

In [19]: for s, i in enumerate(l,1):
    ...:     print(l[:s])
    ...:     
[48]
[48, 52]
[48, 52, 55]
[48, 52, 55, 48]
[48, 52, 55, 48, 52]
[48, 52, 55, 48, 52, 55]
[48, 52, 55, 48, 52, 55, 60]
[48, 52, 55, 48, 52, 55, 60, 62]
[48, 52, 55, 48, 52, 55, 60, 62, 48]

Also, you will get an error message at the very beginning in your code.

In [1]: from collections import Counter

In [2]: c = collections.Counter()
---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
<ipython-input-2-927bc8fd8136> in <module>()
----> 1 c = collections.Counter()

NameError: name 'collections' is not defined

In [3]: c = Counter()

In [4]: c
Out[4]: Counter()

RE: List showing running total of instances - Mekire - Jan-18-2017

I don't think collections.Counter offers much here as you need to do it every step.

One loop will do:

sequence = 48,52,55,48,52,55,60,62,48

result = []
cum_count = {}
for num in sequence:
    cum_count[num] = cum_count.get(num, 0) + 1
    result.append(cum_count[num])

print(result)

Output:
[1, 1, 1, 2, 2, 2, 1, 1, 3]

RE: List showing running total of instances - wavic - Jan-18-2017

I was thinking that this is homework Think

Very generously Cool

RE: List showing running total of instances - micseydel - Jan-18-2017

There was some arguably off-topic discussion which I've split out into https://python-forum.io/Thread-split-Time-Complexity-of-Counting

RE: Dictionary showing running total of instances - Pie_Fun - Jan-20-2017

Hi thanks for the feedback and all the responses

Ok First thing for any future viewers

i screwed up the copy and paste -
should have been

from collections import Counter
AList = [1,2,1,2,3,2,1]
BList = []
CList = []
c = collections.Counter()
myDict = {}
count = 1
for x in AList:
   BList.append(x)
   for y in BList:
       CList.append(y)
       c.update(CList)
       BList = []
   myDict[count] = {'notecount':dict(c)}
   count = count + 1
   c = collections.Counter()

re: >> Also, you will get an error message at the very beginning in your code.
Funny, I'm not getting that error (I'm running from a python tab in maya dont know if that would be any reason)

thanks for the various suggestions - some useful things to know. wavic - Just to clarify I should have titled my original post 'dictionary showing..." rather than 'list showing..'. As I need to be able access the key:value for the coding in maya. What I've coded works for me but over engineered so the winner is Mekire Wink

.(got something on your mind? )

cum_count

Thanks of course. I've just tweaked it for my needs.