The examples below use a variety of infix functions that can be used to change values in a vector.
If you already know indices of the columns or rows you want to change, these functions will not be shorter, however often the opposite is the case, one knows a name, but not the exact column/row number. In these cases the infix functions are much shorter.
d <- data.frame(x=1:5, y=6, txt=paste0("delta = ",6-1:5), row.names=paste0("ri",5:1), stringsAsFactors = FALSE)
knitr::kable(d)| x | y | txt | |
|---|---|---|---|
| ri5 | 1 | 6 | delta = 5 |
| ri4 | 2 | 6 | delta = 4 |
| ri3 | 3 | 6 | delta = 3 |
| ri2 | 4 | 6 | delta = 2 |
| ri1 | 5 | 6 | delta = 1 |
# Change a column name based on the current name
# colnames(d)[colnames(d)%in%"y"] <- "Yhat"
colnames(d)["y"%ci%d] <- "Yhat"
1:3%ci%d
> [1] "x" "Yhat" "txt"
# Use a range of values in variable to change cells
# d$txt[d$x>=2&d$x<=4] <- "Changed!"
d$txt[d$x%[]%c(2,4)] <- "Changed!"
knitr::kable(d)| x | Yhat | txt | |
|---|---|---|---|
| ri5 | 1 | 6 | delta = 5 |
| ri4 | 2 | 6 | Changed! |
| ri3 | 3 | 6 | Changed! |
| ri2 | 4 | 6 | Changed! |
| ri1 | 5 | 6 | delta = 1 |
# Use row names to change cells
# d$txt[rownames(d)%in%c("ri2,ri4")] <- "Changed again!"
d$txt[c("ri2","ri4")%ri%d] <- "Changed again!"
knitr::kable(d)| x | Yhat | txt | |
|---|---|---|---|
| ri5 | 1 | 6 | delta = 5 |
| ri4 | 2 | 6 | Changed again! |
| ri3 | 3 | 6 | Changed! |
| ri2 | 4 | 6 | Changed again! |
| ri1 | 5 | 6 | delta = 1 |
Use the rose tinted glasses %00% to change any nasty
number into a cute fluffy value of your choice.
The counter infix functions can add or subtract values from an input source. This can be a value, or an object.
# Signed increment
# Notice the difference between passing an object and a value for counter
# Value
(11 %+-% -5)
> [1] 6
(11 %+-% 5)
> [1] 16
# Object
i <- 11
(i %+-% -5)
> [1] 6
(i %+-% 5)
> [1] 11
# This means we can use the infix in a while ... statement
# WARNING: As is the case for any while ... statement, be careful not to create an infinite loop!
i <- 5
while(i > -5){
i %+-% -1
print(i)
}
> [1] 4
> [1] 3
> [1] 2
> [1] 1
> Warning in i %+-% -1: Positive valued counter changed sign (counter <= 0)!
> [1] 0
> [1] -1
> [1] -2
> [1] -3
> [1] -4
> [1] -5 # Non-negative increment
# Notice the difference between passing an object and a value for counter
# Value
(0 %++% 5)
> [1] 5
(0 %++% 5)
> [1] 5
# Object
i <- 0
(i %++% 5)
> [1] 5
(i %++% 5)
> [1] 10
# This means we can use the infix in a while ... statement
# WARNING: As is the case for any while ... statement, be careful not to create an infinite loop!
i <- 0
while(i < 20){
i %++% 5
print(i)
}
> [1] 5
> [1] 10
> [1] 15
> [1] 20Use x %[+% n to add n 0s to
the front of x. Similarly, %+]% would add to
the rear, and %[+]% to front and rear. If you want to add a
value other than 0, use x %[+% c(n,v)
set.seed(1234)
(x <- round(runif(10,1,10)))
> [1] 2 7 6 7 9 7 1 3 7 6
# Pad front with 10 zeros
x%[+%5
> [1] 0 0 0 0 0 2 7 6 7 9 7 1 3 7 6
# Same as
x%[+% c(5,0)
> [1] 0 0 0 0 0 2 7 6 7 9 7 1 3 7 6
# Pad rear with zeros
x%+]%5
> [1] 2 7 6 7 9 7 1 3 7 6 0 0 0 0 0
# Same as
x%+]%c(5,0)
> [1] 2 7 6 7 9 7 1 3 7 6 0 0 0 0 0
# Pad front + rear with NA
x%[+]%c(4,NA)
> [1] NA NA 2 7 6 7 9 7 1 3 7 6 NA NA
# Pad front + rear of a character vector
"yes"%[+]%c(2,"no")
> [1] "no" "yes" "no"
"yes"%[+]%c(1,"no")
> [1] "yes" "no"
"yes"%[+]%c(0,"no")
> [1] "yes"Use x %[-% n, x %-]% n, or
x %[-]% c(n,m) to trim x by n
from the front, rear, or, n from the front and
m fro the rear. When n is uneven,
floor(n) wil be trimmed from the front and
ceiling(n) from the rear.