lookup: Look up individual-associated data from one dataset and...
In Eiriksen/fishytools: What the Package Does (One Line, Title Case)

Similar to merge(), but more flexible (and slower). Supports renaming of columns and overwrite-controll. Returns the "to" dataframe with new columns from "from" added.

1	lookup(to, from, what, by, by.x, by.y, new_name, default = NA, overwrite = F)

`to`	A data frame (x) you want to add data from another set into
`from`	The data (y) frame you want to obtain this data from
`what`	Which columns from y to look up into x. Single chr value or vector with multiple values. Will take all columns from y if unspecified.
`by`	Which column to use for identifying individuals. The function only adds data to columns with matching identifiers.
`by.x`	If the identifier has a different column name in the "to" dataset, specify it with by.x
`by.y`	If the identifier has a different column name in the "from" dataset, specify it with by.y
`new_name`	If you want to rename some columns from y before inserting into x. Must be same length as "what". Use an empty "" for columns to stay the same.
`default`	If inserted columns doesn't exist yet in x, use this to specify the default value in case some rows can't be looked up
`overwrite`	If there is already a value in x where one is to be inserted from y, use this to specify if it should be overwritten or not

1	all_people = lookup(to=all_people, from=phone_book, what=c("phone_number","adress"), new_name=("mobile", ""), by="name", by.x="Name", default="not found")