How to parse a python list for largest N values?

Question

I have attached data at the bottom of this post. I have output from another program that I would like to parse in python in a reasonable way.

The output will always be in the same form, and what I would like to do is find out which "tag" has the largest value. I've labeled a truncated version of the data below (and labeled the top of the column)

0        1               2                3            4        5            6          7              8         
AlII     1.6272514892aa  0.0000042282     5.85216aa    0.68792  10.741103    0.074253   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 1.000E+00 0.000E+00
AlII     1.6273145922ab  0.0000129136     0.50000ab    1.41279  10.483775    0.516978   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 1.000E+00 0.000E+00
MgII     1.6272514892AA  0.0000000000     5.85217AA    0.00000  11.510502    3.9484     0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00

So what I'd like to do is parse this file in a number of ways. From the abbreviated one above I'd like to return the following:

Largest (column 2): AlII ab: 0.0000129136
Largest (column 4): AlII ab: 1.41279
Largest (column 6): MgII AA: 3.9484

And I'd actually like to do the top N largest values, but for the example I'll just do the largest. I'm getting bogged down by creating new lists, and finding the indexes of these new lists. Is there some straightforward way of doing this kind of parsing? Or is it going to be a messy process?

EDIT

I've been asked to give some code showing what I've tried.

import numpy as np
analyseList = []
with open('output.ascii', 'r') as f18:
  for line in f18.read().splitlines():
    analyseList.append(line.split())

for column in [2, 4, 6]:
  winner = analyseList[np.argmax(np.column_stack(np.array(analyseList))[column])]
  print winner[0], winner[1][-2:], winner[column]

Of course this only returns the largest value (and I'd like to be able to do the N largest). Also, it just looks like I'm doing it in the least straightforward way possible.

To get the index values of the top N largest values, I can do (using the suggestion from ):

[list(analyse_array[2]).index(x) for x in heapq.nlargest(5, analyse_array[2])]

Am I doing some super-convoluted stuff?

AlII     1.6272514892aa  0.0000042282     5.85216aa    0.68792  10.741103    0.074253   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 1.000E+00 0.000E+00
AlII     1.6273145922ab  0.0000129136     0.50000ab    1.41279  10.483775    0.516978   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 1.000E+00 0.000E+00
AlII     1.6273482473ac  0.0000118688     2.01059ac    3.95256  10.714536    0.646238   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 1.000E+00 0.000E+00
AlII     1.6273975034ad  0.0000379662     3.78319ad    5.42225  11.118654    0.683413   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 1.000E+00 0.000E+00
AlII     1.6274362338ae  0.0000137972     2.17566ae    2.17134  11.105118    1.025574   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 1.000E+00 0.000E+00
AlII     1.6274729985af  0.0000071899     2.59672af    1.62035  11.686851    0.218038   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 1.000E+00 0.000E+00
AlII     1.6275047836ag  0.0000059328     0.56225ag    0.73486  10.908730    0.729322   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 1.000E+00 0.000E+00
AlII     1.6275333529ah  0.0000063501     2.46788ah    1.66430  11.280185    0.381467   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 1.000E+00 0.000E+00
AlII     1.6275811952ai  0.0000273404     4.39490ai    3.90964  11.154901    0.430842   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 1.000E+00 0.000E+00
AlII     1.6276822766ak  0.0000153451     3.86075ak    1.01659  11.687808    0.302170   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 1.000E+00 0.000E+00
AlII     1.6277080822al  0.0000041420     2.77773al    0.74546  11.515588    0.594305   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 1.000E+00 0.000E+00
AlII     1.6277357442am  0.0000180202     3.03343am    2.97410  11.311138    0.474284   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 1.000E+00 0.000E+00
AlII     1.6277884119an  0.0000100139     3.05039an    1.49107  11.218137    0.271466   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 1.000E+00 0.000E+00
AlII     1.6278358107cd  0.0000488929     3.80549cd    6.28261  11.103154    1.305702   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 1.000E+00 0.000E+00
AlII     1.6278657638ao  0.0000095109     4.23025ao    1.26277  11.681221    0.419769   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 1.000E+00 0.000E+00
AlII     1.6279139560bq  0.0000074039     2.68827bq    1.66201  11.457767    0.630426   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 1.000E+00 0.000E+00
AlII     1.6280021360cb  0.0000058565     1.55711cb    1.67734  11.188839    0.706256   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 1.000E+00 0.000E+00
AlII     1.6280408039cc  0.0000168737     3.88995cc    2.74610  11.520547    0.303991   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 1.000E+00 0.000E+00
AlII     1.6279628448ar  0.0000059612     4.02312ar    2.18053  11.975320    0.228508   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 1.000E+00 0.000E+00
AlII     1.6280940230as  0.0000033920     0.61137as    0.37590  10.717869    0.253534   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 1.000E+00 0.000E+00
AlII     1.6281299959at  0.0000035012     0.90119at    0.58387  10.833329    0.072094   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 1.000E+00 0.000E+00
AlII     1.6281673440au  0.0000048884     0.50000au    0.84155  10.339533    0.191522   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 1.000E+00 0.000E+00
AlII     1.6282125019av  0.0000068319     7.51956av    1.17482  11.097728    0.069789   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 1.000E+00 0.000E+00
MgII     1.6272514892AA  0.0000000000     5.85217AA    0.00000  11.510502    0.039484   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgII     1.6273145922AB  0.0000000000     0.50000AB    0.00000  11.176308    0.522596   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgII     1.6273482473AC  0.0000000000     2.01060AC    0.00000  11.450444    0.591724   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgII     1.6273975034AD  0.0000000000     3.78320AD    0.00000  11.803555    0.736543   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgII     1.6274362338AE  0.0000000000     2.17568AE    0.00000  11.967321    0.821801   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgII     1.6274729985AF  0.0000000000     2.59673AF    0.00000  12.458430    0.235348   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgII     1.6275047836AG  0.0000000000     0.56231AG    0.00000  11.941490    0.332862   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgII     1.6275333529AH  0.0000000000     2.46790AH    0.00000  12.037696    0.343867   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgII     1.6275811952AI  0.0000000000     4.39491AI    0.00000  11.840805    0.451418   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgII     1.6276822766AK  0.0000000000     3.86076AK    0.00000  12.497054    0.314167   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgII     1.6277080822AL  0.0000000000     2.77775AL    0.00000  12.391999    0.522446   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgII     1.6277357442AM  0.0000000000     3.03344AM    0.00000  12.112177    0.481882   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgII     1.6277884119AN  0.0000000000     3.05040AN    0.00000  12.013911    0.321297   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgII     1.6278358107CD  0.0000000000     3.80550CD    0.00000  12.061481    1.335432   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgII     1.6278657638AO  0.0000000000     4.23025AO    0.00000  12.520703    0.551397   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgII     1.6279139560BQ  0.0000000000     2.68828BQ    0.00000  12.419351    0.538659   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgII     1.6280021360CB  0.0000000000     1.55713CB    0.00000  11.993443    0.736608   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgII     1.6280408039CC  0.0000000000     3.88996CC    0.00000  12.272450    0.312588   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgII     1.6279628448AR  0.0000000000     4.02313AR    0.00000  12.836074    0.241956   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgII     1.6280940230AS  0.0000000000     0.61143AS    0.00000  11.738664    0.119798   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgII     1.6281299959AT  0.0000000000     0.90123AT    0.00000  11.522748    0.084764   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgII     1.6281673440AU  0.0000000000     0.50000AU    0.00000  11.179284    0.155217   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgII     1.6282125019AV  0.0000000000     7.51956AV    0.00000  11.963228    0.066024   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgII     1.6282950406aw  0.0000162434     0.50000aw   18.49632  10.153640    0.769463   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 1.000E+00 0.000E+00
FeII     1.6276822766AK  0.0000000000     3.86071AK    0.00000  11.593048    0.330634   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
FeII     1.6277080822AL  0.0000000000     2.77768AL    0.00000  11.784789    0.214666   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
FeII     1.6277884119AN  0.0000000000     3.05033AN    0.00000  11.072150    0.276522   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
FeII     1.6278358107CD  0.0000000000     3.80545CD    0.00000  11.147939    1.295144   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
FeII     1.6278657638AO  0.0000000000     4.23021AO    0.00000  11.660933    0.468554   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
FeII     1.6279139560BQ  0.0000000000     2.68821BQ    0.00000  11.427745    0.662669   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
FeII     1.6280021360CB  0.0000000000     1.55700CB    0.00000  10.341299    3.837088   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
FeII     1.6280408039CC  0.0000000000     3.88991CC    0.00000  11.289446    0.290091   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
FeII     1.6279628448AR  0.0000000000     4.02308AR    0.00000  11.989071    0.212467   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
FeII     1.6280940230AS  0.0000000000     0.61111AS    0.00000   9.766184    1.484659   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
FeII     1.6281299959AT  0.0000000000     0.90101AT    0.00000  10.590012    0.186610   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
FeII     1.6281673440AU  0.0000000000     0.50000AU    0.00000  10.186119    0.472566   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
FeII     1.6282125019AV  0.0000000000     7.51954AV    0.00000  11.190375    0.088965   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
AlIII    1.6272514892AA  0.0000000000     5.85216AA    0.00000  10.321950    0.459616   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
AlIII    1.6273145922AB  0.0000000000     0.50000AB    0.00000  10.097437    0.853198   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
AlIII    1.6273482473AC  0.0000000000     2.01059AC    0.00000  10.102194    1.947396   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
AlIII    1.6273975034AD  0.0000000000     3.78319AD    0.00000  11.105979    0.686387   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
AlIII    1.6274362338AE  0.0000000000     2.17566AE    0.00000  11.175948    0.814687   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
AlIII    1.6274729985AF  0.0000000000     2.59672AF    0.00000  11.548086    0.275875   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
AlIII    1.6275047836AG  0.0000000000     0.56225AG    0.00000  11.108123    0.386412   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
AlIII    1.6275333529AH  0.0000000000     2.46788AH    0.00000  11.292689    0.333124   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
AlIII    1.6275811952AI  0.0000000000     4.39490AI    0.00000  11.057781    0.453329   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
AlIII    1.6276822766AK  0.0000000000     3.86075AK    0.00000  11.265981    0.325767   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
AlIII    1.6277080822AL  0.0000000000     2.77773AL    0.00000  11.117329    0.630136   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
AlIII    1.6277357442AM  0.0000000000     3.03343AM    0.00000  10.921103    0.639479   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
AlIII    1.6277884119AN  0.0000000000     3.05039AN    0.00000  11.191087    0.159695   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
AlIII    1.6278657638AO  0.0000000000     4.23025AO    0.00000  11.504725    0.162766   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
AlIII    1.6279139560BQ  0.0000000000     2.68827BQ    0.00000  11.185086    0.780060   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
AlIII    1.6280021360CB  0.0000000000     1.55711CB    0.00000  10.744751    1.475204   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
AlIII    1.6280408039CC  0.0000000000     3.88995CC    0.00000  11.471091    0.278311   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
AlIII    1.6279628448AR  0.0000000000     4.02312AR    0.00000  11.854733    0.209241   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
AlIII    1.6280940230AS  0.0000000000     0.61137AS    0.00000  10.205223    0.810373   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
AlIII    1.6281299959AT  0.0000000000     0.90119AT    0.00000  10.823697    0.155524   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
AlIII    1.6281673440AU  0.0000000000     0.50000AU    0.00000  10.582535    0.258096   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
AlIII    1.6282125019AV  0.0000000000     7.51956AV    0.00000  10.874901    0.182424   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgI      1.6272514892AA  0.0000000000     5.85217AA    0.00000   9.963618    0.199973   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgI      1.6273975034AD  0.0000000000     3.78320AD    0.00000  10.008887    0.626172   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgI      1.6274362338AE  0.0000000000     2.17568AE    0.00000  10.029316    0.772678   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgI      1.6274729985AF  0.0000000000     2.59673AF    0.00000  10.171716    0.390966   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgI      1.6275047836AG  0.0000000000     0.56231AG    0.00000   9.914891    0.378870   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgI      1.6275333529AH  0.0000000000     2.46790AH    0.00000  10.075757    0.224531   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgI      1.6276822766AK  0.0000000000     3.86076AK    0.00000  10.525614    0.306759   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgI      1.6277080822AL  0.0000000000     2.77775AL    0.00000  10.460383    0.403447   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgI      1.6277357442AM  0.0000000000     3.03344AM    0.00000   9.791121    0.536106   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgI      1.6278657638AO  0.0000000000     4.23025AO    0.00000  10.746795    0.126158   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgI      1.6279139560BQ  0.0000000000     2.68828BQ    0.00000  10.134445    0.921959   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgI      1.6280021360CB  0.0000000000     1.55713CB    0.00000   9.964342    0.676227   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgI      1.6280408039CC  0.0000000000     3.88996CC    0.00000  10.126811    0.368050   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgI      1.6279628448AR  0.0000000000     4.02313AR    0.00000  10.750671    0.228670   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgI      1.6280940230AS  0.0000000000     0.61143AS    0.00000   9.405961    0.588696   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgI      1.6281299959AT  0.0000000000     0.90123AT    0.00000   9.292788    0.728340   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00
MgI      1.6281673440AU  0.0000000000     0.50000AU    0.00000   9.807055    0.210571   0.0000E+00QA  0.0000E+00  0 [   0.000   0.000 0.000E+00 0.000E+00

example code always helps us help you better. What have you tried so far? — Martijn Pieters
– Martijn Pieters, Commented Sep 1, 2012 at 10:04

Jon Clements · Accepted Answer · 2012-09-03 10:19:54Z

1

Assuming that you have a list-of-lists to start with, you could do something using just the stdlib(untested and most certainly will need tweaking) such as:

import heapq
from operator import itemgetter

# get a two tuple of (idx, row)
list_with_index = enumerate(your_list)

# Get the top 10 from column '1' and return a list of those
# which will be (row_index, original_row)
largest = heapq.nlargest(10, list_with_index, key=itemgetter(1, 1))

# Get the top 5 index values
largest_indices = [el[0] for el in largest]
# or map(itemgetter(0), largest) if you prefer...

Based on your example code (again untested):

for colno in (2, 4, 6):
    largest = map(itemgetter(0), heapq.nlargest(10, enumerate(analyseList), key=itemgetter(1, colno)))
    print '{} largest: {}'.format(colno, ', '.join(largest))

On a side note you could also consider looking at .argsort on a numpy array.

edited Sep 3, 2012 at 10:19

answered Sep 1, 2012 at 11:06

Jon Clements

143k34 gold badges254 silver badges288 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

JBWhitmore Over a year ago

so I can do this: [list(analyse_array[2]).index(x) for x in heapq.nlargest(5, analyse_array[2])] which will return the top 5 index values from column 2 of the output. Is this along the lines of what you're suggesting?

Jon Clements Over a year ago

@JBWhitmore updated to show how to retrieve indices... You've already got the index as part of the result - you don't need to re-search to find it... Read through my comments...

Pierre GM · Accepted Answer · 2012-09-01 14:41:16Z

1

Have you access to the NumPy package? You could load your whole 2D list in a single ndarray (if you want, with the first string column too). Then you could use the argmax method of your array to find the position of the maximum along each column using argmax(axis=0) or each line argmax(axis=1)...

Assuming that you construct your array column by column, you could do:

analyse_array = np.column_stack(analyse_list)
col_max = analyse_array.argmax(axis=0)

That gives you an array giving the position of the maximum for each column, as the index of the row. If you want the results only for columns 2, 4, 6, just use fancy indexing:

col_max[[2,4,6]]

That way, you can retrieve the corresponding rows as

analyse_array[col_max[[2,4,6]]]

edited Sep 1, 2012 at 14:41

answered Sep 1, 2012 at 10:30

Pierre GM

20.5k3 gold badges58 silver badges67 bronze badges

1 Comment

JBWhitmore Over a year ago

I've added some code showing what I've tried... any suggestions on what to do from here?

Collectives™ on Stack Overflow

How to parse a python list for largest N values?

2 Answers 2

2 Comments

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related