Bernard Szlachta at 09:02, 5 March 2016

2016-03-05T09:02:04Z

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[[Category:Intro to R|050]]

==Exercises==

'''45. Exercise'''

Find employees earning more than the manager’s average.
ENAME SAL
1 BUSH 5000
2 BLAIR 2850
4 PUTIN 2975
10 TOOSK 3000
12 CARNEGIE 3000

<div style="color:white">
emp[SAL > mean(emp[JOB=='MANAGER',]$SAL),c("ENAME","SAL")]
</div>

'''46. Exercise*'''

Select employees earning the maximum salaries in their positions (jobs). Sort results by salary.
Hint: Use data.table package.
ENAME JOB SAL
1 CARNEGIE ANALYST 3000
2 TOOSK ANALYST 3000
4 ELISON CLERK 1300
9 PUTIN MANAGER 2975
10 BUSH PRESIDENT 5000
12 BAROSSO SALESMAN 1600

<div style="color:white">
emp.maxsal <- merge(emp,emp.dt[,max(SAL),by=JOB])

with(emp.maxsal,emp.maxsal[SAL==V1,c("ENAME","JOB","SAL")])
</div>

'''47. Exercise*'''

Find employees hired first in their departments.
ENAME DEPTNO HIREDATE
3 MERKEL 10 1981-06-09
5 THATCHER 20 1980-12-17
14 BAROSSO 30 1981-02-20

<div style="color:white">
emp.minhiredate <- merge(emp,emp.dt[,min(HIREDATE),by=DEPTNO])

with(emp.minhiredate,emp.minhiredate[HIREDATE==V1,c("ENAME","DEPTNO","HIREDATE")])
</div>

'''48. *Exercise'''

Generate a report, which computes the following sums.
10 20 30
ANALYST NA 6000 NA
CLERK 1300 1900 950
MANAGER 2450 2975 2850
PRESIDENT 5000 NA NA
SALESMAN NA NA 5600

R - Data Analysis - Revision history

Bernard Szlachta at 09:02, 5 March 2016