R how to remove rows in a data frame based on the first character of a column

Question

I have a big data frame and I want to remove certain rows from it based on first char of a column being a letter or a number. Sample of my data frame looks like a below:

Answer 1

We can use grep. The regex ^ indicates the beginning of the string. We match numeric element ([0-9]) at the beginning of the string in the 'y' column using grep. The output will be numeric index, which we use to subset the rows of the 'abc'.

 abc[grep('^[0-9]', abc$y),]
 #        y          z
 #1 34TA912 23.12.2015
 #4 34CC515 25.12.2015