[SPARK-23461][R]vignettes should include model predictions for some ML models

[huaxingao]

What changes were proposed in this pull request?

Add model predictions for Linear Support Vector Machine (SVM) Classifier, Logistic Regression, GBT, RF and DecisionTree in vignettes.

How was this patch tested?

Manually ran the test and checked the result.

[SparkQA]

Test build #92492 has finished for PR 21678 at commit 85ad256.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[felixcheung]

can you check what the output pdf/html content looks like? we sometimes has a long or unreadable output, that doesn't quite fit in the vignettes

[huaxingao]

Here is the output for Linear SVM Classifier in sparkr-vignettes.html.

prediction <- predict(model, training)
head(select(prediction, "Class", "Sex", "Age", "Freq", "Survived", "prediction"))
##   Class    Sex   Age Freq Survived prediction
## 1   1st   Male Child    0       No        Yes
## 2   2nd   Male Child    0       No        Yes
## 3   3rd   Male Child   35       No        Yes
## 4  Crew   Male Child    0       No        Yes
## 5   1st Female Child    0       No        Yes
## 6   2nd Female Child    0       No        Yes

[felixcheung]

ok then, thanks

[felixcheung]

LGTM

[felixcheung]

merged to master

[huaxingao]

@felixcheung Thanks a lot for your help!