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Suppose I have a decision tree from rpart, How can I get all the data points in one node without writing all the conditions?

For example, How can I get 17 data points in Node 3, without writing if else on all splits?

library(rpart)
library(partykit)
fit=rpart(factor(am)~.,mtcars,control=rpart.control(minsplit = 2),cp=0)
plot(as.party(fit))

enter image description here

Sandipan Dey
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hxd1011
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    http://stackoverflow.com/questions/36748531/getting-the-observations-in-a-rparts-node-i-e-cart – rawr Jan 18 '17 at 18:03

1 Answers1

1

Try this:

fit$where[fit$where==3] # for Node 3
#  Hornet 4 Drive   Hornet Sportabout             Valiant          Duster 360           Merc 240D            Merc 280           Merc 280C 
#              3                   3                   3                   3                   3                   3                   3 
#     Merc 450SE          Merc 450SL         Merc 450SLC  Cadillac Fleetwood Lincoln Continental   Chrysler Imperial    Dodge Challenger 
#              3                   3                   3                   3                   3                   3                   3 
#    AMC Javelin          Camaro Z28    Pontiac Firebird 
              3                   3                   3 
length(fit$where[fit$where==3])
#[1] 17

mtcars[rownames(mtcars) %in% names(fit$where[fit$where==3]),]
#                     mpg cyl  disp  hp drat    wt  qsec vs am gear carb  x
#Hornet 4 Drive      21.4   6 258.0 110 3.08 3.215 19.44  1  0    3    1  4
#Hornet Sportabout   18.7   8 360.0 175 3.15 3.440 17.02  0  0    3    2  5
#Valiant             18.1   6 225.0 105 2.76 3.460 20.22  1  0    3    1  6
#Duster 360          14.3   8 360.0 245 3.21 3.570 15.84  0  0    3    4  7
#Merc 240D           24.4   4 146.7  62 3.69 3.190 20.00  1  0    4    2  8
#Merc 280            19.2   6 167.6 123 3.92 3.440 18.30  1  0    4    4 10
#Merc 280C           17.8   6 167.6 123 3.92 3.440 18.90  1  0    4    4 11
#Merc 450SE          16.4   8 275.8 180 3.07 4.070 17.40  0  0    3    3 12
#Merc 450SL          17.3   8 275.8 180 3.07 3.730 17.60  0  0    3    3 13
#Merc 450SLC         15.2   8 275.8 180 3.07 3.780 18.00  0  0    3    3 14
#Cadillac Fleetwood  10.4   8 472.0 205 2.93 5.250 17.98  0  0    3    4 15
#Lincoln Continental 10.4   8 460.0 215 3.00 5.424 17.82  0  0    3    4 16
#Chrysler Imperial   14.7   8 440.0 230 3.23 5.345 17.42  0  0    3    4 17
#Dodge Challenger    15.5   8 318.0 150 2.76 3.520 16.87  0  0    3    2 22
#AMC Javelin         15.2   8 304.0 150 3.15 3.435 17.30  0  0    3    2 23
#Camaro Z28          13.3   8 350.0 245 3.73 3.840 15.41  0  0    3    4 24
#Pontiac Firebird    19.2   8 400.0 175 3.08 3.845 17.05  0  0    3    2 25
Sandipan Dey
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