Computing Quantiles for a column in R to subset

r

Solution

You can do this using `cut` and `quantile`.

# some data
df <- data.frame(name=letters , am.spent = rnorm(26))

# divide df$am.spent 
df$qnt<- cut(df$am.spent , breaks=quantile(df$am.spent),
                                    labels=1:4, include.lowest=TRUE)

 # check ranges
 tapply(df$am.spent , df$qnt , range)

First get the `quantile` quantile(df$am.spent)

#        0%        25%        50%        75%       100% 
#-3.5888426 -0.6879445 -0.1461107  0.5835165  1.2030989

Then use `cut` to divide df$am.spent at specified cutpoints - we cut at the values of the quantiles. This is specified with the `breaks`argument

Problem

I have a data set with the following structure: ``` Name=c("a","b","c") Amount_Spent=c(386407,213918,212006) ``` What I am trying to do is compute which quartile the `Amount_Spent` falls under for each name and assign the value to a new variable (column) `Quantiles`. I am not able to use any of the apply functions to get this result, can someone help please? Thanks in advance, Raoul

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