remove character columns from a numeric data frame <p>I have a data frame like the one you see here. </p> <pre><code> DRSi TP DOC DN date Turbidity Anions 158 5.9 3371 264 14/8/06 5.83 2246.02 217 4.7 2060 428 16/8/06 6.04 1632.29 181 10.6 1828 219 16/8/06 6.11 1005.00 397 5.3 1027 439 16/8/06 5.74 314.19 2204 81.2 11770 1827 15/8/06 9.64 2635.39 307 2.9 1954 589 15/8/06 6.12 2762.02 136 7.1 2712 157 14/8/06 5.83 2049.86 1502 15.3 4123 959 15/8/06 6.48 2648.12 1113 1.5 819 195 17/8/06 5.83 804.42 329 4.1 2264 434 16/8/06 6.19 2214.89 193 3.5 5691 251 17/8/06 5.64 1299.25 1152 3.5 2865 1075 15/8/06 5.66 2573.78 357 4.1 5664 509 16/8/06 6.06 1982.08 513 7.1 2485 586 15/8/06 6.24 2608.35 1645 6.5 4878 208 17/8/06 5.96 969.32 </code></pre> <p>Before I got here i used the following code to remove those columns that had no values at all or some NA's. </p> <pre><code> rem = NULL for(col.nr in 1:dim(E.3)[2]){ if(sum(is.na(E.3[, col.nr]) &gt; 0 | all(is.na(E.3[,col.nr])))){ rem = c(rem, col.nr) } } E.4 &lt;- E.3[, -rem] </code></pre> <p>Now I need to remove the "date" column but not based on its column name, rather based on the fact that it's a character string. </p> <p>I've seen here (<a href="http://stackoverflow.com/questions/6286313/remove-an-entire-column-from-a-data-frame-in-r">remove an entire column from a data.frame in R</a>) already how to simply set it to NULL and other options but I want to use a different argument. </p>