Using both text and argument in same function in R-CodePudding

First of all need to create the same data;

library(tibbletime)
date <- seq(from = as.Date("1979-09-01"), to = as.Date("2019-12-01"), by = "month")
n <- length(date)
df <- matrix(NA, n, 2)
df <- data.frame(df)
var <- sample(1000:5000, n)
df[1] <- date
df[2] <- var
names(df) <- c("date", "var")
df <- as_tbl_time(df, index = date)

How can i use command below;

filter_time(df, ~"1979-09")

by paste0, eval(parse(text = "") I tried that one;

filter_time(eval(parse(text = paste0("df",",", "~" , "1979-09",sep = ""))))

but it didn't work. I have problem with time object which must be as text format. If that code works, it is possible to use in for loop, thanks.

CodePudding user response：

We could use reformulate to construct the expression

library(tibbletime)
filter_time(df, reformulate(termlabels = dQuote("1979-09", FALSE)))

-output

# A time tibble: 1 × 2
# Index: date
  date         var
  <date>     <int>
1 1979-09-01  1700

CodePudding user response：

You can also accomplish this with as.formula()

filter_time(df, as.formula(paste0("~", '"', year, '"')))

Full reprex:

library(tibbletime)

date <- seq(from = as.Date("1979-09-01"), to = as.Date("2019-12-01"), by = "month")
n <- length(date)
df <- matrix(NA, n, 2)
df <- data.frame(df)
var <- sample(1000:5000, n)
df[1] <- date
df[2] <- var
names(df) <- c("date", "var")
df <- as_tbl_time(df, index = date)

year <- paste("1979-09")
paste0("~", '"', year, '"')
#> [1] "~\"1979-09\""

as.formula(paste0("~", '"', year, '"'))
#> ~"1979-09"

filter_time(df, as.formula(paste0("~", '"', year, '"')))
#> # A time tibble: 1 x 2
#> # Index: date
#>   date         var
#>   <date>     <int>
#> 1 1979-09-01  3600