Make Frequency Histogram for Factor Variables

Question

I am very new to R  so I apologize for such a basic question  I spent an hour googling this issue  but couldn t find a solution   Say I have some categorical data in my data set about common pet types  I input it as a character vector in R that contains the names of different types of animals  I created it like this    animals  lt - c  cat    dog     dog    dog    dog    dog    dog    dog    cat    cat    bird     I turn it into a factor for use with other vectors in my data frame   animalFactor  lt - as factor animals    I now want to create a histogram that shows the frequency of each variable on the y-axis  the name of each factor on the x-axis  and contains one bar for each factor  I attempt this code   hist table animalFactor   freq TRUE  xlab   levels animalFactor   ylab    Frequencies     The output is absolutely nothing like I d expect  Labeling problems aside  I can t seem to figure out how to create a simple frequency histogram by category

User · Accepted Answer

It seems like you want barplot prop table table animals        However  this is not a histogram

User · Answer

You could also use lattice  histogram

User · Answer

If you d like to do this in ggplot  an API change was made to geom histogram   that leads to an error  https   github com hadley ggplot2 issues 1465  To get around this  use geom bar     animals  lt - c  cat    dog     dog    dog    dog    dog    dog    dog    cat    cat    bird    library ggplot2    counts ggplot data frame animals   aes x animals       geom bar

User · Answer

The reason you are getting the unexpected result is that hist      calculates the distribution from a numeric vector  In your code  table animalFactor  behaves like a numeric vector with three elements  1  3  7  So hist      plots the number of 1 s  1   the number of 3 s  1   and the number of 7 s  1    Roland s solution is the simplest    Here s a way to do this using ggplot   library ggplot2  ggp  lt - ggplot data frame animals  aes x animals     counts ggp   geom histogram fill  lightgreen     proportion ggp   geom histogram fill  lightblue  aes y   count   sum   count          You would get precisely the  same result using animalFactor instead of animals in the code above

User · Answer

Data as factor can be used as input to the plot function   An answer to a similar question has been given here  https   stat ethz ch pipermail r-help 2010-December 261873 html   x sample c  Richard    Minnie    Albert    Helen    Joe    Kingston       50  replace T   x as factor x   plot x

User · Answer

Country is a categorical variable and I want to see how many occurences of country exist in the data set  In other words  how many records attendees are from each Country   barplot summary df Country

[r] Make Frequency Histogram for Factor Variables

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