cd N:\workshop\May2015
clear all
set more off

sysuse auto, clear 


*Example 1: Attach the prefix _78 to the variables named price and mpg

foreach v in price mpg { 
	rename `v' `v'_78
}

*The following is equivalent:
foreach v of varlist price mpg { 
	rename `v' `v'_78
}

********************************************************************************
*Example 2: Count the number of observations in this dataset
local counter = 0 
local N = _N

forvalues i = 1 / `N' {
	local counter = `counter'+1
}

display `counter'
*Note that this exactly what the count command does.

********************************************************************************
*Example 3: Count the number of observations in this dataset

local counter = 1 
local N = _N

while `counter' < `N' {
	local counter = `counter'+1
}

display `counter'

********************************************************************************
*Example 4: Count the number of foreign and domestic vehicles
local count1 = 0 
local count0 = 0 
local N = _N

forval orig = 0/1 { 
	forval row = 1/`N' {
		if foreign[`row'] == `orig' {
			local count`orig' = `count`orig'' + 1
		}
	}
}

display "No. of foreign cars: `count1'" 
display "No. of domestic cars: `count0'"