# 
# Written by:
# -- 
# John L. Weatherwax                2009-04-21
# 
# email: wax@alum.mit.edu
# 
# Please send comments and especially bug reports to the
# above email address.
# 
#-----

#
# EPage 139
#

save_plots = F

Table_6_8_DF = read.csv( "../../Data/US_attitudes.csv", header=TRUE )

# Produce a spaghetti plot for this data:
#
Table_6_8_DF_long = reshape( Table_6_8_DF, varying=c( "Year_1999_2000", "Summer_2000", "March_2003", "June_2003" ), v.names=c( "attitudes" ), timevar="time", idvar="country", direction="long" )
rownames(Table_6_8_DF_long) = NULL

# Lets check our long format is "correct":
#
inds = Table_6_8_DF_long$country == "Great Britain"
print( Table_6_8_DF_long[inds,] )
##          country time attitudes
## 2  Great Britain    1        83
## 22 Great Britain    2        75
## 42 Great Britain    3        48
## 62 Great Britain    4        70

inds = Table_6_8_DF_long$country == "Pakistan"
print( Table_6_8_DF_long[inds,] )
##     country time attitudes
## 18 Pakistan    1        23
## 38 Pakistan    2        10
## 58 Pakistan    3        NA
## 78 Pakistan    4        13

# We now have our data in a format we can use to make a spaghetti plot:
#
# http://www.ats.ucla.edu/stat/r/faq/spagplot.htm
#
if( save_plots ){ postscript("../../WriteUp/Graphics/Chapter6/ex_7_spaghetti_plot.eps", onefile=FALSE, horizontal=FALSE) }
interaction.plot(Table_6_8_DF_long$time, Table_6_8_DF_long$country, Table_6_8_DF_long$attitudes,
                 xlab="time", ylab="country attitude", main="spaghetti plot of attitude by country", legend=F)
if( save_plots ){ dev.off() }