R dataframe sorted by a column

Usage scenarios: randomly generated value as is, so no sequence x distinction (plotting Figure 1), so to use to sort the data re-mapping (mapping Figure II)
x <-rnorm (n-, 0 ,. 5)
E <-rnorm (n-, 0, 0.01)
Y <-10 0.8 + X. 3 + X ^ 2 + 0.1 X ^ + E. 3
Y1 <-11.7 + 0.538 X + 2.93 * X ^{2 * X + 0.097} . 3
DATA2 <-data.frame (X, Y1)
DATA3 <-DATA2 [Sort (DATA2 $x,index.return=TRUE)$ix,]
plot(x,y)
#lines(x,y1)
lines(data3 $x,data3$ Y1, COL = '# fe8463', LWD = 2)
Figure 1:
Figure 2: