StackOverflow2013

Note that there are some explanatory texts on larger screens.

plurals

PO
text
Body
copied!<p>A solution with <code>combn</code> and <code>apply</code>:</p> <pre><code>cc <- combn(colnames(ex)[1:4], 2) apply(cc, 2, function(x)ex[[x[1]]]-ex[[x[2]]]) </code></pre> <p>gives for the first 5 rows:</p> <pre><code> [,1] [,2] [,3] [,4] [,5] [,6] [1,] -0.43500930 -0.520148152 0.1602265 -0.08513885 0.59523580 0.680374655 [2,] -0.32964090 -0.153303302 -0.3807295 0.17633760 -0.05108855 -0.227426149 [3,] 0.25991705 -0.079679566 0.2040904 -0.33959662 -0.05582670 0.283769917 [4,] 0.35585252 0.153083047 0.2382553 -0.20276948 -0.11759719 0.085172292 [5,] -0.67081018 -0.116543468 -0.3413471 0.55426671 0.32946305 -0.224803663 </code></pre> <p><strong>Edit</strong> </p> <p>As Arun suggested, combn can take a function argument, so a better solution is </p> <pre><code>res <- combn(colnames(ex)[1:4], 2, function(x) ex[[x[1]]] - ex[[x[2]]]) colnames(res) <- combn(colnames(ex)[1:4], 2, paste, collapse="_") as.data.table(res) AAA_BBB AAA_CCC AAA_DDD BBB_CCC BBB_DDD CCC_DDD 1: -0.4350093 -0.52014815 0.16022650 -0.08513885 0.59523580 0.68037465 2: -0.3296409 -0.15330330 -0.38072945 0.17633760 -0.05108855 -0.22742615 3: 0.2599171 -0.07967957 0.20409035 -0.33959662 -0.05582670 0.28376992 4: 0.3558525 0.15308305 0.23825534 -0.20276948 -0.11759719 0.08517229 5: -0.6708102 -0.11654347 -0.34134713 0.55426671 0.32946305 -0.22480366 --- 999996: -0.8450458 -0.47951267 -0.30333929 0.36553310 0.54170648 0.17617338 999997: -0.5778393 -0.01784418 -0.24353237 0.55999516 0.33430697 -0.22568819 999998: 0.7127352 0.82554276 0.01258673 0.11280758 -0.70014846 -0.81295604 999999: -0.6693544 -0.42335069 -0.81080852 0.24600375 -0.14145408 -0.38745783 1000000: -0.8511655 -0.23341818 -0.15830584 0.61774732 0.69285966 0.07511234 </code></pre>

Querying!

Guidance

An individual column

Larger individual text columns get their own page to allow for proper reading.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload