Storing the last iteration in a loop(python)

Question

So I have 2 variables mean and service consisting of the following values:

mean=[5.76,6.5,7,5,4.5,6,9,2.5,3,5.5]
limit=[90,80,95,96,98,85,82,75,90,91]

Now,I have applied poisson function on the variable mean:

from scipy.stats import poisson
for m in mean:
    r_v=poisson(m)
    r_v1.append(r_v)

Next what I need to do is obtain the sum of pmfs of all the values of mean(with the number of occurrences starting from 0) and compare those to the corresponding values in limit. I need to obtain the number of occurrence for which the sum of pmfs is greater than or equal to the corresponding value in limit. For example, for mean =5.76, (pmf(0)+pmf(1)...+pmf(9))*100=93.2, which exceeds 90 in the limit variable for 9 occurences. I've run the following code which seems to work fine:

for r,s in zip(r_v1, limit):
        l=[]
        z=0
        while True:
            y=r.pmf(z)
            l.append(y)
            z+=1
            if round(sum(l),2)*100>=s:
                break
Store=%z

The issue is, when I'm trying to store the last occurrence of z at which round(sum(l),2)*100>=s, I'm getting the following error:

ERROR:root:Line magic function `%z` not found.

Can somebody please help me rectify the error in the code? Thanks a lot.

hi, Store=z is not giving me the number of occurrences. I had read somewhere that %helps you obtain the last iteration or something like that. I'm not exactly sure how to go about it. — IndigoChild, Jan 28 '18 at 04:36
As I've mentioned in the example, I need to obtain z for which the sum of pmfs will be greater than or equal to the corresponding values under the column limit. — IndigoChild, Jan 28 '18 at 04:54
And is the result for your example 10? Because that's what I get, but I don't now how to verify. — Darkonaut, Jan 28 '18 at 04:57
9 i guess, but I think you're on the right track. can you store it for all the 10 observations in an array? — IndigoChild, Jan 28 '18 at 05:05
youre're right it will be 10, since the iteration starts from 0. Can you store it for all the obs? — IndigoChild, Jan 28 '18 at 05:06
so for mean =5.76 you got 10 iterations right? I need the number of iterations for all the values of mean similarly, to be stored in some variable which I can print/display subsequently. — IndigoChild, Jan 28 '18 at 05:25
You're welcome! Still don't quite understand what you're actually doing here so... ;) — Darkonaut, Jan 28 '18 at 06:29
its an operations research based case study actually. thanks anyway! — IndigoChild, Jan 28 '18 at 06:32

Darkonaut · Accepted Answer · 2018-01-28T18:50:35.607

% is the prefix for invoking magic line functions within IPython's interactive shell and there is no z line magic function, hence you get this error.

type %quickref in IPython and you get an overview over the available magic functions or readthedocs.

Your problem was that you were trying too much in one step. Try getting the right result for one input and then accumulate in another step:

def calc(mean_, limit_):

    def inner(m, s):
        r = poisson(m)
        l = []
        z = 0
        while True:
            y = r.pmf(z)
            l.append(y)
            z += 1
            if round(sum(l), 2) * 100 >= s:
                return z, l

    return [inner(*args) for args in zip(mean_, limit_)]

Calling calc(mean, limit) gives:


[(10,
  [0.0031511115984444414,
   0.018150402807039979,
   0.052273160084275148,
   0.10036446736180832,
   0.14452483300100394,
   0.16649260761715656,
   0.15983290331247035,
   0.13151964615426115,
   0.094694145231068075,
   0.060604252947883679]),
 (10,
  [0.0015034391929775724,
   0.009772354754354215,
   0.031760152951651209,
   0.068813664728577653,
   0.11182220518393866,
   0.14536886673912017,
   0.1574829389673803,
   0.14623415761256733,
   0.11881525306021086,
   0.08581101609904139]),
 (12,
  [0.00091188196555451624,
   0.0063831737588816145,
   0.022341108156085643,
   0.052129252364199796,
   0.091226191637349643,
   0.1277166682922895,
   0.14900277967433773,
   0.14900277967433773,
   0.1303774322150455,
   0.10140466950059107,
   0.070983268650413558,
   0.045171170959354162]),
 (10,
  [0.006737946999085467,
   0.033689734995427337,
   0.084224337488568321,
   0.1403738958142805,
   0.17546736976785063,
   0.17546736976785068,
   0.1462228081398754,
   0.10444486295705395,
   0.065278039348158651,
   0.036265577415643714]),
 (10,
  [0.011108996538242306,
   0.049990484422090385,
   0.11247858994970336,
   0.168717884924555,
   0.18980762054012446,
   0.17082685848611215,
   0.1281201438645839,
   0.082362949627232548,
   0.046329159165318316,
   0.0231645795826592]),
 (9,
  [0.0024787521766663585,
   0.014872513059998144,
   0.044617539179994441,
   0.089235078359988937,
   0.13385261753998332,
   0.16062314104797995,
   0.16062314104798009,
   0.13767697804112569,
   0.10325773353084421]),
 (13,
  [0.00012340980408667956,
   0.0011106882367801166,
   0.0049980970655105232,
   0.014994291196531574,
   0.033737155192196056,
   0.06072687934595293,
   0.091090319018929264,
   0.1171161244529091,
   0.13175564000952278,
   0.13175564000952278,
   0.11858007600857066,
   0.097020062188830414,
   0.072765046641622894]),
 (4,
  [0.0820849986238988,
   0.20521249655974699,
   0.25651562069968376,
   0.21376301724973648]),
 (6,
  [0.049787068367863944,
   0.14936120510359185,
   0.22404180765538775,
   0.22404180765538775,
   0.16803135574154085,
   0.10081881344492458]),
 (10,
  [0.0040867714384640666,
   0.02247724291155237,
   0.06181241800676901,
   0.1133227663457432,
   0.15581880372539689,
   0.17140068409793663,
   0.15711729375644187,
   0.12344930223720431,
   0.084871395288077939,
   0.051865852676047694])]

Storing the last iteration in a loop(python)

1 Answers1