modify_in | R Documentation |
assign_in()
takes a data structure and a pluck location,
assigns a value there, and returns the modified data structure.
modify_in()
applies a function to a pluck location, assigns the
result back to that location with assign_in()
, and returns the
modified data structure.
modify_in(.x, .where, .f, ...) assign_in(x, where, value)
.x, x |
A vector or environment |
.where, where |
A pluck location, as a numeric vector of positions, a character vector of names, or a list combining both. The location must exist in the data structure. |
.f |
A function to apply at the pluck location given by |
... |
Arguments passed to |
value |
A value to replace in |
pluck()
# Recall that pluck() returns a component of a data structure that # might be arbitrarily deep x <- list(list(bar = 1, foo = 2)) pluck(x, 1, "foo") # Use assign_in() to modify the pluck location: str(assign_in(x, list(1, "foo"), 100)) # Or zap to remove it str(assign_in(x, list(1, "foo"), zap())) # Like pluck(), this works even when the element (or its parents) don't exist pluck(x, 1, "baz") str(assign_in(x, list(2, "baz"), 100)) # modify_in() applies a function to that location and update the # element in place: modify_in(x, list(1, "foo"), \(x) x * 200) # Additional arguments are passed to the function in the ordinary way: modify_in(x, list(1, "foo"), `+`, 100)
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