Message-ID: <687088457.8022659.1406919490250.JavaMail.zimbra@stanford.edu>
Date: 2014-08-01T18:58:10Z
From: Stephen HK Wong
Subject: How to randomly extract a number of rows in a data frame
Dear ALL,
I have a dataframe contains 4 columns and several 10 millions of rows like below! I want to extract out "randomly" say 1 millions of rows, can you tell me how to do that in R using base packages? Many Thanks!!!!
Col_1 Col_2 Col_3 Col_4
chr1 3000215 3000250 -
chr1 3000909 3000944 +
chr1 3001025 3001060 +
chr1 3001547 3001582 +
chr1 3002254 3002289 +
chr1 3002324 3002359 -
chr1 3002833 3002868 -
chr1 3004565 3004600 -
chr1 3004945 3004980 +
chr1 3004974 3005009 -
chr1 3005115 3005150 +
chr1 3005124 3005159 +
chr1 3005240 3005275 -
chr1 3005558 3005593 -
chr1 3005890 3005925 +
chr1 3005929 3005964 +
chr1 3005913 3005948 -
chr1 3005913 3005948 -
Stephen HK Wong