如何在dplyr中更改循环 [英] How to mutate for loop in dplyr

问题描述

我想为数据框中的一列创建多个滞后变量，以获取一系列值.我的代码可以成功完成我想做的事情，但不能满足我的需要(数百次迭代)

I want to create multiple lag variables for a column in a data frame for a range of values. I have code that successfully does what I want but is not scalable for what I need (hundreds of iterations)

下面有我的代码，可以成功完成我想做的事，但不能满足我的需要(数百次迭代)

I have code below that successfully does what I want but is not scalable for what I need (hundreds of iterations)

Lake_Lag <- Lake_Champlain_long.term_monitoring_1992_2016 %>% 
group_by(StationID,Test) %>% 
   arrange(StationID,Test,VisitDate) %>% 
   mutate(lag.Result1 = dplyr::lag(Result, n = 1, default = NA))%>% 
   mutate(lag.Result5 = dplyr::lag(Result, n = 5, default = NA))%>% 
   mutate(lag.Result10 = dplyr::lag(Result, n = 10, default = NA))%>% 
   mutate(lag.Result15 = dplyr::lag(Result, n = 15, default = NA))%>% 
   mutate(lag.Result20 = dplyr::lag(Result, n = 20, default = NA))

我希望能够使用列表c(1,5,10,15,20)或范围1:150为数据框创建滞后变量.

I would like to be able to use a list c(1,5,10,15,20) or a range 1:150 to create lagging variables for my data frame.

推荐答案

这是一种利用来自 rlang 的 dplyr 中包含的整洁的评估助手"的方法.code>包.

Here's an approach that makes use of some 'tidy eval helpers' included in dplyr that come from the rlang package.

基本思想是在 mutate()中创建一个新列，其名称基于for循环提供的字符串.

The basic idea is to create a new column in mutate() whose name is based on a string supplied by a for-loop.

library(dplyr)

grouped_data <- Lake_Champlain_long.term_monitoring_1992_2016 %>% 
  group_by(StationID,Test) %>% 
  arrange(StationID,Test,VisitDate)

for (lag_size in c(1, 5, 10, 15, 20)) {

  new_col_name <- paste0("lag_result_", lag_size)

  grouped_data <- grouped_data %>% 
    mutate(!!sym(new_col_name) := lag(Result, n = lag_size, default = NA))
}

sym(new_col_name):= 是在使用<

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