# PrepHistogram: This function transform standard variables into... In GraphPCA: Graphical Tools of Histogram PCA

## Description

This function transforms quantitative variable into histogram-valued variable.

## Usage

 `1` ```PrepHistogram(X, Z = NULL, k = 3,group=NULL) ```

## Arguments

 `X` `X` quantitative variable that need to be transformed into symbolic histogram `Z` `Z` categorical variable that need to be used for the purpose of clustering `k` `k` number of bins of histogram-valued variables `group` Data group

## Value

Returns a list including :

 `mido ` return the class centres of class and the min and the max of histograms `Vhistogram` dataframe containing the relative frequency of histogram variables

## Author(s)

Brahim Brahim Brahim Brahim <brahim.brahim@bigdatavisualizations.com> and Sun Makosso-Kallyth <makosso.sun@gmail.com>

## References

Makosso-Kallyth, Sun; Diday, Edwin. Adaptation of interval PCA to symbolic histogram variables. Advances in Data Analysis and Classification. Volume 6. n 2. 2012. pages 147-159. Springer.

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31``` ```### example1 from iris data ## preparation of histogram-valued variables (k= 3 bins) Sepal.LengthHistogram=PrepHistogram(X=iris[,1],Z=iris[,5])\$Vhistogram Sepal.WidthHistogram=PrepHistogram(X=iris[,2],Z=iris[,5])\$Vhistogram Petal.LengthHistogram=PrepHistogram(X=iris[,3],Z=iris[,5])\$Vhistogram Petal.WidthHistogram=PrepHistogram(X=iris[,4],Z=iris[,5])\$Vhistogram ############################ Hitsogram PCA ################################# HistPCA(Variable=list(Sepal.LengthHistogram,Sepal.WidthHistogram, Petal.LengthHistogram,Petal.WidthHistogram), Row.names=names(table(iris[,5])), Col.names=colnames(iris)[1:4]) ### example2 from iris data ## preparation of histogram-valued variables (k= 4 bins) Sepal.LengthHistogram=PrepHistogram(X=iris[,1],Z=iris[,5],k=2)\$Vhistogram Sepal.WidthHistogram=PrepHistogram(X=iris[,2],Z=iris[,5],k=2)\$Vhistogram Petal.LengthHistogram=PrepHistogram(X=iris[,3],Z=iris[,5],k=2)\$Vhistogram Petal.WidthHistogram=PrepHistogram(X=iris[,4],Z=iris[,5],k=2)\$Vhistogram ############################ Hitsogram PCA ################################# HistPCA(Variable=list(Sepal.LengthHistogram,Sepal.WidthHistogram, Petal.LengthHistogram,Petal.WidthHistogram), Row.names=names(table(iris[,5])),Col.names=colnames(iris)[1:4]) ```