Consider this data structure (df1) ...
Group Year PctProf FullYr
1 Never RF 2004 87 88
2 Cohort 1 2004 83 84
3 Cohort 2 2004 84 86
4 Cohort 3 2004 87 87
5 Cohort 4 2004 73 74
6 Never RF 2005 85 86
7 Cohort 1 2005 81 82
8 Cohort 2 2005 81 81
9 Cohort 3 2005 78 79
10 Cohort 4 2005 72 74
11 Never RF 2006 83 84
12 Cohort 1 2006 78 78
13 Cohort 2 2006 78 79
14 Cohort 3 2006 70 71
15 Cohort 4 2006 80 82
16 Never RF 2007 82 83
17 Cohort 1 2007 75 76
18 Cohort 2 2007 73 74
19 Cohort 3 2007 79 80
20 Cohort 4 2007 75 77
21 Never RF 2008 83 84
22 Cohort 1 2008 81 81
23 Cohort 2 2008 81 81
24 Cohort 3 2008 76 77
25 Cohort 4 2008 62 63
... which I subsetted to omit all cases for Cohort 4 and some cases for
Cohorts 2 & 3 ...
df2 <- subset(df1,
((Group == "Cohort 1" | Group == "Never RF") | (Group ==
"Cohort 2"
& Year != 2004) |
(Group == "Cohort 3" & Year > 2006)))
> df2
Group Year PctProf FullYr
1 Never RF 2004 87 88
2 Cohort 1 2004 83 84
6 Never RF 2005 85 86
7 Cohort 1 2005 81 82
8 Cohort 2 2005 81 81
11 Never RF 2006 83 84
12 Cohort 1 2006 78 78
13 Cohort 2 2006 78 79
16 Never RF 2007 82 83
17 Cohort 1 2007 75 76
18 Cohort 2 2007 73 74
19 Cohort 3 2007 79 80
21 Never RF 2008 83 84
22 Cohort 1 2008 81 81
23 Cohort 2 2008 81 81
24 Cohort 3 2008 76 77
Now,
> table(df2$Group)
... properly shows 0 cases for the Group level "cohort 4" ...
Cohort 1 Cohort 2 Cohort 3 Cohort 4 Never RF
5 4 2 0 5
But when I plot ...
coll = c("violet","blue","green","red")
with(df2, interaction.plot(Year, Group, FullYr,
lwd=3,col=coll, bty="l", lty=1, las=1,
ylab="Percent Proficient", xlab="",
main = "Proficiency Trends for RF and Non-RF Schools"))
... I get the four lines that I expected but the legend includes the
Group level "cohort 4" .
How can I get rid of "cohort 4" in Group?
Thanks!
Art
------------------------------------------------------------------
Art Burke
Northwest Regional Educational Laboratory
101 SW Main St, Suite 500
Portland, OR 97204-3213
Phone: 503-275-9592 / 800-547-6339
Fax: 503-275-0450
burkea@nwrel.org
[[alternative HTML version deleted]]
Arthur Burke wrote:> > ... I get the four lines that I expected but the legend includes the > Group level "cohort 4" . > > How can I get rid of "cohort 4" in Group? >This link might be of interest for you: http://wiki.r-project.org/rwiki/doku.php?id=tips:data-manip:drop_unused_levels hth Stefan
krzysztof.sakrejda at gmail.com
2009-May-27 20:54 UTC
[R] Factor level with no cases shows up in a plot
If you have a vector of factors with empty levels you can get rid of them by
rerunning the vector through the factor function:
vec <- factor(vec)
Don't know if this can be done at plotting time...
Sent via BlackBerry by AT&T
-----Original Message-----
From: "Arthur Burke" <burkea at nwrel.org>
Date: Wed, 27 May 2009 11:46:12
To: <r-help at r-project.org>
Subject: [R] Factor level with no cases shows up in a plot
Consider this data structure (df1) ...
Group Year PctProf FullYr
1 Never RF 2004 87 88
2 Cohort 1 2004 83 84
3 Cohort 2 2004 84 86
4 Cohort 3 2004 87 87
5 Cohort 4 2004 73 74
6 Never RF 2005 85 86
7 Cohort 1 2005 81 82
8 Cohort 2 2005 81 81
9 Cohort 3 2005 78 79
10 Cohort 4 2005 72 74
11 Never RF 2006 83 84
12 Cohort 1 2006 78 78
13 Cohort 2 2006 78 79
14 Cohort 3 2006 70 71
15 Cohort 4 2006 80 82
16 Never RF 2007 82 83
17 Cohort 1 2007 75 76
18 Cohort 2 2007 73 74
19 Cohort 3 2007 79 80
20 Cohort 4 2007 75 77
21 Never RF 2008 83 84
22 Cohort 1 2008 81 81
23 Cohort 2 2008 81 81
24 Cohort 3 2008 76 77
25 Cohort 4 2008 62 63
.... which I subsetted to omit all cases for Cohort 4 and some cases for
Cohorts 2 & 3 ...
df2 <- subset(df1,
((Group == "Cohort 1" | Group == "Never RF") | (Group ==
"Cohort 2"
& Year != 2004) |
(Group == "Cohort 3" & Year > 2006)))
> df2
Group Year PctProf FullYr
1 Never RF 2004 87 88
2 Cohort 1 2004 83 84
6 Never RF 2005 85 86
7 Cohort 1 2005 81 82
8 Cohort 2 2005 81 81
11 Never RF 2006 83 84
12 Cohort 1 2006 78 78
13 Cohort 2 2006 78 79
16 Never RF 2007 82 83
17 Cohort 1 2007 75 76
18 Cohort 2 2007 73 74
19 Cohort 3 2007 79 80
21 Never RF 2008 83 84
22 Cohort 1 2008 81 81
23 Cohort 2 2008 81 81
24 Cohort 3 2008 76 77
Now,
> table(df2$Group)
... properly shows 0 cases for the Group level "cohort 4" ...
Cohort 1 Cohort 2 Cohort 3 Cohort 4 Never RF
5 4 2 0 5
But when I plot ...
coll = c("violet","blue","green","red")
with(df2, interaction.plot(Year, Group, FullYr,
lwd=3,col=coll, bty="l", lty=1, las=1,
ylab="Percent Proficient", xlab="",
main = "Proficiency Trends for RF and Non-RF Schools"))
... I get the four lines that I expected but the legend includes the
Group level "cohort 4" .
How can I get rid of "cohort 4" in Group?
Thanks!
Art
------------------------------------------------------------------
Art Burke
Northwest Regional Educational Laboratory
101 SW Main St, Suite 500
Portland, OR 97204-3213
Phone: 503-275-9592 / 800-547-6339
Fax: 503-275-0450
burkea at nwrel.org
[[alternative HTML version deleted]]
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