在这篇文章中,我们将学习如何使用R编程语言中的dplyr对每个组应用一个函数。R语言中的dplyr包用于数据操作和修改。该包可以通过以下命令下载并安装到工作空间。install.packages("dplyr") R Copy什么是tibbletibble是R语言中一种类似于数据框架的结构,它包含以表格结构排列的行和列。它说明了数据框架的列的数据类型...
dplyr::summarise_each(iris, funs(mean)) Apply summary function to each column. dplyr::count(iris, Species, wt = Sepal.Length) Count number of rows with each unique value of variable (with or without weights). dplyr::mutate(iris, sepal = Sepal.Length + Sepal. Width) ...
mutate(iris,sepal=Sepal.Length+Sepal.Width) #Apply window function to each column. mutate_each(iris, funs(min_rank)) # Compute one or more new columns.Drop original columns transmute(iris,sepal=Sepal.Length + Sepal.Width) window function Mutate uses window functions,functions that take a ...
下面是这样的例子: library(dplyr)as.data.frame(matrix(1:12, 4)) %>% mutate(Res = apply(as.matrix(.), 1, ifelse(Function, ~mean, ~sd), na.rm = TRUE)) 然而,这样我得到了下面的错误: Error: Problem with `mutate()` column你能帮助我正确地应用条件来选择函数</e 浏览23提问于2021-10-...
Apply a function to certain columns only, by rows mtcars%>%select(am,gear,carb)%>%purrr::by_row(sum,.collate="cols",.to="sum_am_gear_carb")->mtcars2 head(mtcars2) ## # A tibble: 6 × 4## am gear carb sum_am_gear_carb## <dbl> <dbl> <dbl> <dbl>## 1 1 4 4 9## ...
今天接到一个群友的需求，有一张表的数据如图 1，他希望能通过 SQL 查询出图 2 的结果。
ofeachcallshouldbeomitted-thevalueofthepreviousstepwillbesubstituted inautomatically.Usechainand...whenworkinginteractive;usechain_q andcallswhencallingfromanotherfunction. envEnvironmentinwhichtoevaluationexpressions.Inordinaryoperationyou shouldnotneedtosetthisparameter. lhs,rhsAdatasetandfunctiontoapplytoit Details...
The functions in theover-apply function familycreate columns by applying one or several functions to: dplyr::across()a set of columns (not part of dplyover) over()a vector (list or atomic vector) over2()two vectors of the same length (sequentially#) ...
A new family of functions replace summarise_each() and mutate_each() (which will thus be deprecated in a future release). summarise_all() and mutate_all() apply a function to all columns while summarise_at() and mutate_at() operate on a subset of columns. These columuns are selected ...
使用rowSums对每行求和（rowwise适用于任何聚合，但速度较慢）