Using IF statement on Delta value in R

Can anyone please let me know how to make a IF loop on a Delta value? For Example; giving a Delta value = 2, works as below; Check IF (output is between in +2 and -2) and i also want to include 2 and -2 in a check. If condition fulfills, save it in a vector else discard it. I am using below mentioned data.

 longitude <- round(c(48.7188021250007,
                 48.7188133749999,
                 48.7188291249998,
                 48.7188336250004, 
                 48.7188291250005, 
                 48.7188291250085
                 ), 8);

 Latitude <- round(c (2.39514523661229,
                 2.39512477447308, 
                 2.39472235230961,
                 2.39467460730213,
                 2.39467460730313, 
                 2.4), 8);

Thanks