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ValueError: sample larger than population
Sekuri Jouri
edited Jun 10, 2014

Not sure why I'm getting this runtime error now as I'm sure it's worked for me before. Here's the code I'm using:

import random

def initialize(context):  
    set_universe(universe.DollarVolumeUniverse(floor_percentile=99.0, ceiling_percentile=100.0))  
    context.portSize = 2

def handle_data(context, data):  
    selected = random.sample(data, context.portSize)  
    log.debug('Sample assets: {selected}'.format(selected=selected))

and when I run it I get:
Runtime exception: ValueError: sample larger than population

Doesn't seem to matter the start/end dates or daily/minutely runs.
I've got to be missing something silly.

1 response
Alisa Deychman
Jun 10, 2014

Hi Sekuri,

Before we load the full data to start a backtest, we quickly screen your code for syntax errors and run a quick loop against dummy data. This makes it faster to find code issues, but occasionally causes problems like this to crop up.

Here's a fix to make your algo run: 

import random

def initialize(context):  
    set_universe(universe.DollarVolumeUniverse(floor_percentile=99.0, ceiling_percentile=100.0))  
    context.portSize = 2

def handle_data(context, data):  
    if len(data) > context.portSize:  
        selected = random.sample(data, context.portSize)  
        log.debug('Sample assets: {selected}'.format(selected=selected))
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The material on this website is provided for informational purposes only and does not constitute an offer to sell, a solicitation to buy, or a recommendation or endorsement for any security or strategy, nor does it constitute an offer to provide investment advisory services by Quantopian.

In addition, the material offers no opinion with respect to the suitability of any security or specific investment. No information contained herein should be regarded as a suggestion to engage in or refrain from any investment-related course of action as none of Quantopian nor any of its affiliates is undertaking to provide investment advice, act as an adviser to any plan or entity subject to the Employee Retirement Income Security Act of 1974, as amended, individual retirement account or individual retirement annuity, or give advice in a fiduciary capacity with respect to the materials presented herein. If you are an individual retirement or other investor, contact your financial advisor or other fiduciary unrelated to Quantopian about whether any given investment idea, strategy, product or service described herein may be appropriate for your circumstances. All investments involve risk, including loss of principal. Quantopian makes no guarantees as to the accuracy or completeness of the views expressed in the website. The views are subject to change, and may have become unreliable for various reasons, including changes in market conditions or economic circumstances.