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1. Rcommands
By: Dr. Preeti Jindal
Associate Professor
TIAS

2. How to see your file
•Summary(File_name)

3. How to see particular variable
• Summary(file_name$variable_name)

4. How to create variable
• Variable_name=file_name$variable_name

5. How to see particular variable
• Summary(Variable_name)

6. How to see class of particular variable
• Class(variable_name)

7. How to convert character variable into
factor
• Variable_name=as.factor(file_name$variable_name)

8. How to see levels of factor variable
• Levels(categorical variable_name)

9. How to see level-wise summary of
categorical variable
• Summary(gender)

10. How to calculate percentage
• Variablename=summary(variablename)
• Variablename/total no. of respondents

11. How to create variable instantly
•X=1

12. R as calculator
• X+1= 2
• Sd(X)
• Squart(x)
• Log(X)

13. Remove variable
• Remove(X)

14. Mean of any metric variable
• Mean(variable_name)

15. Standard Deviation and variance of
metric variable
• sd(V1)
• var(v1)

16. All data frame
• all=data.frame(v1,v2,v3.....vn)

17. All file’s details
• All then press enter

18. Summary of all
• Summary(all) then press enter

19. Row and Column
• File_name[1:6,1:2]
• File_name[1;6,]

20. Mean of particular variable
• Mean(metric variable[gender==“Male”])

21. Tapply function
• Tapply(vector, index,function)

22. Aggregate function
• Aggregate(metric var.~categorical
V1+categorical V2, FUN=mean)

23. Making codes readable
• age=factor(age,labels=c(lessthan 18, 18-24,
25-30, morethan 40))

24. Cross-tabs
• It applies when both variables are categorical
• table(gender,background)

25. Chi-square test
• t=table(gender,background)
• Chisq test(t)

26. barplot
• Barplot(t)
• Barplot(t,beside=T)

27. T test
• One sample t-test
• It applies when we have one metric variable
and we checks its average value against a
claim.
• Null hypothesis is that calculated mean is
equal to claimed mean.

28. One sample t-test
• T.test(metric variable name, mu=claimed
value)

29. Two independent sample t-test
• T.test(metric variable~categorical variable,
var.equal=T)