How to perform paired t test for multiple columns in R?

Output

$y1 Welch Two Sample t-test data: x by df$x1
t = 0.90555, df = 17.683, p-value = 0.3773
alternative hypothesis: true difference in means is not equal to 0
95 percent confidence interval:
-1.190729 2.990729
sample estimates:
mean in group A mean in group B
5.5 4.6
$y2 Welch Two Sample t-test data: x by df$x1
t = -1.057, df = 15.664, p-value = 0.3065
alternative hypothesis: true difference in means is not equal to 0
95 percent confidence interval:
-1.8054596 0.6054596
sample estimates:
mean in group A mean in group B
1.1 1.7
$y3 Welch Two Sample t-test data: x by df$x1
t = -0.55089, df = 17.802, p-value = 0.5886
alternative hypothesis: true difference in means is not equal to 0
95 percent confidence interval:
-3.853392 2.253392
sample estimates:
mean in group A mean in group B
10.1 10.9
$y4 Welch Two Sample t-test data: x by df$x1
t = 0.92338, df = 16.062, p-value = 0.3695
alternative hypothesis: true difference in means is not equal to 0
95 percent confidence interval:
-0.7770541 1.9770541
sample estimates:
mean in group A mean in group B
2.2 1.6
$y5 Welch Two Sample t-test data: x by df$x1
t = 0.14907, df = 17.521, p-value = 0.8832
alternative hypothesis: true difference in means is not equal to 0
95 percent confidence interval:
-1.312111 1.512111
sample estimates:
mean in group A mean in group B
2.2 2.1