dudi.coa: Correspondence Analysis

In ade4: Analysis of Ecological Data : Exploratory and Euclidean Methods in Environmental Sciences

Description

performs a correspondence analysis.

Usage

dudi.coa(df, scannf = TRUE, nf = 2)

Arguments

df	a data frame containing positive or null values
scannf	a logical value indicating whether the eigenvalues bar plot should be displayed
nf	if scannf FALSE, an integer indicating the number of kept axes

Value

returns a list of class coa and dudi (see dudi) containing

N	the sum of all the values of the initial table

Author(s)

Daniel Chessel
Anne B Dufour [e-mail]

References

Benzécri, J.P. and Coll. (1973) L'analyse des données. II L'analyse des correspondances, Bordas, Paris. 1–620.

Greenacre, M. J. (1984) Theory and applications of correspondence analysis, Academic Press, London.

Examples

data(rpjdl)
chisq.test(rpjdl$fau)$statistic
rpjdl.coa <- dudi.coa(rpjdl$fau, scannf = FALSE, nf = 4)
sum(rpjdl.coa$eig)*rpjdl.coa$N # the same

if(adegraphicsLoaded()) {
  g1 <- s.label(rpjdl.coa$co, plab.cex = 0.6, lab = rpjdl$frlab, plot = FALSE)
  g2 <- s.label(rpjdl.coa$li, plab.cex = 0.6, plot = FALSE)
  cbindADEg(g1, g2, plot = TRUE)
} else {
  par(mfrow = c(1,2))
  s.label(rpjdl.coa$co, clab = 0.6, lab = rpjdl$frlab)
  s.label(rpjdl.coa$li, clab = 0.6)
  par(mfrow = c(1,1))
}

data(bordeaux)
db <- dudi.coa(bordeaux, scan = FALSE)
db
score(db)

Example output

X-squared 
 7323.597 
Warning message:
In chisq.test(rpjdl$fau) : Chi-squared approximation may be incorrect
[1] 7323.597
Duality diagramm
class: coa dudi
$call: dudi.coa(df = bordeaux, scannf = FALSE)

$nf: 2 axis-components saved
$rank: 3
eigen values: 0.5906 0.1102 0.03109
  vector length mode    content       
1 $cw    4      numeric column weights
2 $lw    5      numeric row weights   
3 $eig   3      numeric eigen values  

  data.frame nrow ncol content             
1 $tab       5    4    modified array      
2 $li        5    2    row coordinates     
3 $l1        5    2    row normed scores   
4 $co        4    2    column coordinates  
5 $c1        4    2    column normed scores
other elements: N 

ade4 documentation built on May 2, 2019, 5:50 p.m.