How to create an alluvial plot in ggplot2 with ggalluvial package?

I'm trying to create an alluvial plot in ggplot2 with the ggalluvial package. Here are the two helpful websites I've been using to create the plot: site 1 and site 2.

My goal is to use the same code found on site 1 but apply it to my own df, as shown below. However, everytime I try to do that I get the following error:

Error in data.frame(first_row, curve_data): arguments imply differing number of rows: 1, 12

This is my df:

t1 <- c("college", "college", "college", "university", "university")
t2 <- c("law", "law", "business", "business", "business")
t3 <- c("public", "private", "private", "private", "public")
t4 <- c(2,4,6,8,10)

df <- data.frame(cbind(t1,t2,t3,t4))
names(df) <- c("Undergrad", "Grad_School", "Sector", "Freq")

This is the original code, as copied from site 1:

library(ggalluvial)
vaccinations
ggplot(data = vaccinations,
       aes(axis1 = survey,
           axis2 = response,
           axis3 = survey,
           y = freq)) +
    geom_alluvium(aes(fill = response)) +
    geom_stratum() +
    geom_text(stat = "stratum",
              aes(label = after_stat(stratum))) +
    scale_x_discrete(limits = c("Survey", "Response"),
                     expand = c(0.15, 0.05)) +
    theme_void()

This is my code with my df substituted in.

ggplot(data = df,
       aes(axis1 = Undergrad,
           axis2 = Grad_School,
           y = Freq)) +
    geom_alluvium(aes(fill = Sector)) +
    geom_stratum() +
    geom_text(stat = "stratum",
              aes(label = after_stat(stratum))) +
    scale_x_discrete(limits = c("Undergrad", "Grad_School"),
                     expand = c(0.15, 0.05)) +
    theme_void()

Solution

When you cbind() your vectors, you create a matrix which (unlike a data.frame) cannot contain different data types. Therefore, the Freq gets converted to a character. If you just directly create the data.frame without cbind() it works fine.

library(tidyverse)
library(ggalluvial)

t1 <- c("college", "college", "college", "university", "university")
t2 <- c("law", "law", "business", "business", "business")
t3 <- c("public", "private", "private", "private", "public")
t4 <- c(2,4,6,8,10)

df <- data.frame(t1,t2,t3,t4)
names(df) <- c("Undergrad", "Grad_School", "Sector", "Freq")

ggplot(data = df, 
       aes(axis1 = Undergrad,
             axis2 = Grad_School,
             y = Freq)) +
  geom_alluvium(aes(fill = Sector)) +
  geom_stratum() +
  geom_text(stat = "stratum",
            aes(label = after_stat(stratum))) +
  scale_x_discrete(limits = c("Undergrad", "Grad_School"),
                   expand = c(0.15, 0.05)) +
  theme_void()

^{Created on 2022-07-18 by the reprex package (v2.0.1)}