how to return number of decimal places in R

I am working in R. I have a series of coordinates in decimal degrees, and I would like to sort these coordinates by how many decimal places these numbers have (i.e. I will want to discard coordinates that have too few decimal places).
Is there a function in R that can return the number of decimal places a number has, that I would be able to incorporate into function writing?
Example of input:

AniSom4     -17.23300000        -65.81700

AniSom5     -18.15000000        -63.86700

AniSom6       1.42444444        -75.86972

AniSom7       2.41700000        -76.81700

AniLac9       8.6000000        -71.15000

AniLac5      -0.4000000        -78.00000

I would ideally write a script that would discard AniLac9 and AniLac 5 because those coordinates were not recorded with enough precision. I would like to discard coordinates for which both the longitude and the latitude have fewer than 3 non-zero decimal values.