Add scatter plot points in R-CodePudding

I would like to add my own data into a dataframe, and eventually use that data to generate a scatter plot.

But I am having trouble adding 2D points in R. It seems to me that the data for x-axis and y-axis has to be added separately. However, I have multiple points with the same x-coordinate but different y-coordinates.

I have figured out a way to input my data as shown below. But surely there has to be a more efficient way?

i1 <- seq (85,85, length.out=5)
c1 <- c(55, 62, 61, 73, 76)

i2 <- seq (105,105, length.out=6)
c2 <- c(64, 72, 73, 82, 87, 88)

CodePudding user response：

It's easiest to put data into long format for plotting. Here, I convert all data to numeric, then I pivot to long format, and we can just drop the rows that have NA (i.e., the ones that were blank). I also do not save the column names, but can keep them if important for color coding the points.

library(tidyverse)

df %>% 
  mutate(across(everything(), ~ as.numeric(.))) %>% 
  pivot_longer(-x, names_to = NULL, values_to = "y", values_drop_na = TRUE) %>% 
  ggplot(aes(x = x, y = y))  
  geom_point()

Output

Data

df <- structure(list(x = c(85, 105, 122), y1 = c(55, 64, 79), y2 = c(62, 
72, 84), y3 = c("", "88", "")), class = "data.frame", row.names = c(NA, 
-3L))

CodePudding user response：

The most normal is to introduce data by col:

# several ways to create obs
df = data.frame(X   = c(85,105,122,143,162,182,203,224,242,262),
                Y_1 = 1:10,
                Y_2 = rep(5,10), 
                Y_3 = c(NA,88,NA,113,125,140,NA,160,189,182))

     X Y_1 Y_2 Y_3
1   85   1   5  NA
2  105   2   5  88
3  122   3   5  NA
4  143   4   5 113
5  162   5   5 125
6  182   6   5 140
7  203   7   5  NA
8  224   8   5 160
9  242   9   5 189
10 262  10   5 182

And then we can transform it to longer shape:

library(tidyr)
df_longer = df %>% pivot_longer(!X)

# A tibble: 30 × 3
       X name  value
   <dbl> <chr> <dbl>
 1    85 Y_1       1
 2    85 Y_2       5
 3    85 Y_3      NA
 4   105 Y_1       2
 5   105 Y_2       5
 6   105 Y_3      88
 7   122 Y_1       3
 8   122 Y_2       5
 9   122 Y_3      NA
10   143 Y_1       4
# … with 20 more rows

Scatter plot using base plot:

plot(df_longer$X, df_longer$value)

Using ggplot:

library(ggplot2) 

ggplot(df_longer)   
       geom_point(aes(x = X, y = value, col = name))