因子范围作为R中的函数变量

Question

I have code

ggplot(bywells[bywells$Well_N == "KRT3",], aes(x = Date_m)) +
geom_line(aes(y = QOM, colour = "Oil, m3/month"))

which draw chart. This code works without any errors. Now I would like to elaborate it in function where bywells is variable data and "KRT3" is variable wellname , but if I write like this

simple_fun <- function(data, wellname, ...)
{
   require("ggplot2", quietly=TRUE)
   ggplot(data[data$Well_N == "wellname",], aes(x = Date_m)) +
   geom_line(aes(y = QOM, colour = "Oil, m3/month"))
}

after executing function I get error message

Error: Aesthetics must either be length one, or the same length as the dataProblems:QOM, Date_m

when I try

ggplot(data[wellname == Well_N %in% data,], aes(x = Date_m))

I get

Error in match(x, table, nomatch = 0L) : object 'Well_N' not found

Any hints how can I define it as a variable properly?

For example reproducibility I ad small chunk of data sample:

"Well_N";"Date_m";"QOM";"QWM";"QOMT";"BHP";"PRES";"QIW";"THPI";"QFM";"WCT"
"KRT3";2014-06-30;132;525;108;NA;NA;NA;NA;657;79
"KRT3";2014-07-30;36;120;29;NA;NA;NA;NA;156;76
"KRT3";2014-08-30;39;2.6;32.1;NA;NA;NA;NA;41.6;6.25
"KRT3";2014-09-30;211.274;749.362;174.070;NA;NA;NA;NA;960.636;78
"KRT3";2014-10-30;45;45;37.07;NA;NA;NA;NA;90;50
"KRT4";2014-08-30;108.37;1815.358;90.79;NA;NA;NA;NA;1923.73;94
"KRT4";2014-09-30;161.775;202.87;133;NA;NA;NA;NA;364;55
"KRT4";2014-10-30;30;1680;24;NA;NA;NA;NA;1710;98
"KRT4";2014-11-30;31.8;339;26;NA;NA;NA;NA;370.8;91

Type of Well_N is factor , Date_m is POSIXct , others are num .

Answer 1

Here is the reproducible data (I've left only three columns which are needed, use function dput in your future questions):

bywells <-
structure(list(Well_N = structure(c(1L, 1L, 1L, 1L, 1L, 2L, 2L, 
2L, 2L), .Label = c("KRT3", "KRT4"), class = "factor"), Date_m = structure(c(16251, 
16281, 16312, 16343, 16373, 16312, 16343, 16373, 16404), class = "Date"), 
    QOM = c(132, 36, 39, 211.274, 45, 108.37, 161.775, 30, 31.8
    )), class = "data.frame", row.names = c(NA, -9L), .Names = c("Well_N", 
"Date_m", "QOM"))

Here is the call without the function:

library(dplyr)
library(ggplot2)
library(magrittr)
qplot(x=Date_m, y=QOM, data = bywells %>% filter(Well_N == "KRT3"), geom="line")

Here is the function:

pfun <- function(data,wellname) {
    qplot(x=Date_m, y=QOM, data=data %>% filter(Well_N == wellname), geom="line")
}

with the corresponding call:

pfun(bywells,"KRT3")

Your error was to put the quotes on the variable wellname in the condition which filters the data. Also your colour setting is not ok, since there is no such color called "Oil, m3/month". Aim for English words such as "red", "blue", see colors() for more variants. Colour should be set outside aes argument in order for it to work.