使用 R 获取该范围内的范围和随机天数

Question

我有一个如下所示的数据框

test_df <- data.frame("subbject_id" = c(1,2,3,4,5), 
                      "date_1" = c("01/01/2003","12/31/2007","12/30/2008","01/02/2007","01/01/2007"))
test_df = test_df %>%
  mutate(date_1 = mdy(date_1), 
         previous_year = floor_date(date_1, 'year'), 
         next_year = ceiling_date(date_1, 'year') - 1, 
         days_to_previous_year = as.integer(date_1 - previous_year), 
         days_to_next_year = as.integer(next_year - date_1),
         rand_days_prev_year = sample.int(days_to_previous_year, 1),
         rand_days_next_year = sample.int(days_to_next_year, 1)) %>%
  select(-previous_year, -next_year)

多亏了这个，它帮助我用代码到达了解决方案的一部分。

我想做两件事

a) 使用 days_to_prev_year 和 days_to_next_year 获取值的范围。请注意，days_to_prev_year 前面必须有 minus 符号，如输出所示。

b) 在该范围内选择一个随机值。请注意，如果范围是 [0,364]，我希望随机值介于 [1,364] 之间（包括 ）。我不希望 0 作为随机值。所以，我想避免 0 被选为随机值。同样，如果是[-11,21]。我也不想在这里选择 0，但是兰特值可以是 -11 或 21.

我尝试了下面的语句，但它不起作用

range = paste0("[-",days_to_previous_year,",+",days_to_next_year,"]")
test_df$rand_days = sample.int(test_df$range, 1) # error as non-numeric

所以，我尝试使用以下两个数字列

test_df$rand_days_prev_year = sample.int(test_df$days_to_previous_year, 1) # this doesn't work
test_df$rand_days_next_year = sample.int(test_df$days_to_next_year, 1) # but this works

我收到如下所示的错误消息

Error in if (useHash) .Internal(sample2(n, size)) else .Internal(sample(n,  : 
  missing value where TRUE/FALSE needed

我希望我的输出如下所示

Answer 1

这是一种方法：

library(dplyr)

test_df %>%
  mutate(range = sprintf("%d, %d", -days_to_previous_year, days_to_next_year)) %>%
  rowwise() %>%
  mutate(rand_days = {days = -days_to_previous_year:days_to_next_year;
                      days  = days[days != 0]
                      if(length(days)) sample(days, 1) else NA
                      })

#   subbject_id date_1     days_to_previous_year days_to_next_year range   rand_days
#        <dbl> <date>                     <int>             <int> <chr>       <int>
#1           1 2003-01-01                     0               364 0, 364        206
#2           2 2007-12-31                   364                 0 -364, 0      -220
#3           3 2008-12-30                   364                 1 -364, 1      -274
#4           4 2007-01-02                     1               363 -1, 363       228
#5           5 2007-01-01                     0               364 0, 364         72

使用 R 获取该范围内的范围和随机天数

Get the range and random days within that range using R

datetime

r

dataframe

lubridate

dplyr