Sorting dataframe by column of letters and numbers

Question

I have been attempting to sort my dataframe by the first column - or day - with multiple different methods listed below to no avail. I suspect it could be because it is attempting to order by the first number but I am unsure how I would change that to get it to order the rows properly. The dataset is as follows:

df1
    [day][sample1][sample2]
[1,]day0    22       11
[2,]day11   23       15
[3,]day15   25       14
[4,]day2    21       13
[5,]day8    20       17
...

I am looking to order the entire row by day. I have tried the following

df[sort(as.character(df$day)),]
df[order(as.character(df$day)),]
mixedorder(as.character(df$day))   (gtools package)

The mixedorder merely output an index of numbers.

Current Code:

df_0$day =  metadata_df[,3]
df_0 <- df_0[,c(8,1:7)]
df1 <- aggregate(df_0[,2:ncol(df_0)], df_0[1], mean)
df1 <- df1[mixedorder(as.character(df1$day)),]
df1$day <- factor(df1$day, levels = unique(df1$day))
rownames(df1) <- 1:nrow(df1)
##Plotting expression levels
Plot1 <- ggplot() +
  geom_line(data=df1, aes(x=day, y=sample1, group=1, color="blue"))+
  geom_line(data=df2, aes(x=day, y=sample1, group=2, color="red"))

Note that I have done the same transformations with df2 as I have with df1. Both df1 and df2 are the same, except with slightly different values in them.

Answer 1

The mixedorder gives the ordered index which can be used to order the rows

df1 <- df[mixedorder(as.character(df$day)),]
df1
#     day sample1 sample2
#1  day0      22      11
#4  day2      21      13
#5  day8      20      17
#2 day11      23      15
#3 day15      25      14

---

It is not clear about how the OP is plotting.

library(tidyverse)
df1 %>%
    mutate(day = factor(day, levels = unique(day))) %>% 
    gather(key, val, -day) %>%
    ggplot(., aes(x = day, y = val, color = key)) + 
          geom_point() 

data

df <- structure(list(day = structure(1:5, .Label = c("day0", "day11", 
"day15", "day2", "day8"), class = "factor"), sample1 = c(22L, 
23L, 25L, 21L, 20L), sample2 = c(11L, 15L, 14L, 13L, 17L)), .Names = c("day", 
 "sample1", "sample2"), class = "data.frame", row.names = c(NA, 
-5L))