How to loop to generate graphics in R?

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Consider the following Data Frame: 

ITENS <-c("A","B","C","D","E")
Q.1 <-c(10,20,10,40,10)
Q.2 <-c(5,25,0,50,10)
Q.3 <-c(15,20,5,40,10)
Q.4 <-c(15,30,5,30,5)
Q.5 <-c(20,25,5,20,15)
Q.6 <-c(10,20,10,40,10)
df <- data.frame(ITENS,Q.1,Q.2,Q.3,Q.4,Q.5,Q.6)

Then I use the code below to generate a chart: 

library(ggplot2)
plot.grafico <- ggplot(data=df, aes(x=df$ITENS, y=df$Q.1)) +
geom_bar(stat="identity") +
xlab("Itens") +
ylab("Quantidade de Alunos") +
ggtitle("Titulo")+ guides(fill=FALSE)
plot.grafico

That is, it is a bar graph of column Q.1 of my data frame.
I would like to loop where I could generate the graph of each column.
I currently do the following: 

plot.grafico1 <- ggplot(data=df, aes(x=df$ITENS, y=df$Q.1)) +
geom_bar(stat="identity") +
xlab("Itens") +
ylab("Quantidade de Alunos") +
ggtitle("Titulo")+ guides(fill=FALSE)

plot.grafico2 <- ggplot(data=df, aes(x=df$ITENS, y=df$Q.2)) +
geom_bar(stat="identity") +
xlab("Itens") +
ylab("Quantidade de Alunos") +
ggtitle("Titulo")+ guides(fill=FALSE)

plot.grafico3 <- ggplot(data=df, aes(x=df$ITENS, y=df$Q.3)) +
geom_bar(stat="identity") +
xlab("Itens") +
ylab("Quantidade de Alunos") +
ggtitle("Titulo")+ guides(fill=FALSE)

library(gridExtra)

grid.arrange(plot.grafico1,plot.grafico2,plot.grafico3)

I would like a routine to not be able to repeat the code 6 times
In fact my original frame date has 45 columns.

    
asked by anonymous 10.05.2018 / 02:37

1 answer

2

I think the loop is not the best solution for you. 

# alongue o data frame.
library(tidyr)
long <- df %>% gather(turma, quantidade, Q.1:Q.6)

# use facet_wrap
library(ggplot2)
ggplot(long) + 
  geom_bar(aes(x = ITENS, y = quantidade), stat = "identity") +
  facet_wrap(~turma)

    
10.05.2018 / 04:52
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