如何將map2與不等長的向量一起使用

Question

問題

我正在嘗試計算收入在$ 1到$ 200,000之間且應增加$ 100（2000值）的應交所得稅。

我搜集了有關稅率的信息，得出了34個數據框的列表。

我有一個根據收入和適用稅率計算應納稅額的函數。

使用該函數，我想產生一個顯示應納稅額的向量：

1. 每個收入水平（2000個值）
2. 每套（34套房價）

如果可以在數據幀/小標題中返回此輸出，那就太好了。

數據

#This scrapes the website of the tax administrator and returns a list of tidy data frames showing tax rates for income years between 2016 and 1983
url <- "https://www.ato.gov.au/Rates/Individual-income-tax-for-prior-years/"
pit_sch <- url %>%
  read_html() %>%
  html_table() %>%
  setNames(., url %>%
             read_html() %>%
             html_nodes("caption") %>%
             html_text()) %>% 
  map(.%>%
    mutate(`Tax on this income` = gsub(",", "", `Tax on this income`), 
            cumm_tax_amt = str_extract(`Tax on this income`, "(?<=^\\$)\\d+") %>% as.numeric(), 
            tax_rate = str_extract(`Tax on this income`, "\\d+.(\\d+)?(?=(\\s+)?c)") %>% as.numeric(), 
            threshold = str_extract(`Tax on this income`, "(?<=\\$)\\d+$") %>% as.numeric()
           )
    ) %>%
  map(~drop_na(.x, threshold)) %>% 
  map(function(x) { mutate_each(x, funs(replace(., is.na(.), 0))) })

#Defining income 
income <- seq(from = 1, to = 200000, by = 100)

#The function for calculating tax payable
tax_calc <- function(data, income) {
  i <-tail(which(income >= data[, 5]), 1)
  if (length(i) > 0) 
    return(((income - data[i,5]) * (data[i,4]/100)) + data[i,3])
  else
    return(0)
}

我的嘗試

> map2(pit_sch, income, tax_calc)
Error: Mapped vectors must have consistent lengths:
* `.x` has length 34
* `.y` has length 2000
    enter code here

Answer 1

為了正確地區分不同的income和計算該income年份。 我建議讓tax_calc函數返回一個tibble與income和tax的計算。

library(tidyverse)

tax_calc <- function(data, income) {
   i <-tail(which(income >= data[, 5]), 1)
  if (length(i) > 0) 
    return(tibble(income = income, 
          tax = (income - data[i,5]) * (data[i,4]/100) + data[i,3]))
  else
    return(tibble(income = income, tax = 0))
}

既然你想tax_calc的所有income為每個pit_sch可以使用

map(pit_sch,~map_df(income, tax_calc, data = .)) %>%  bind_rows(., .id = "id")

---

檢查它的tail(income)我們得到

map(pit_sch,~map_df(tail(income), tax_calc, data = .)) %>%  bind_rows(., .id = "id")

# A tibble: 204 x 3
#   id                             income    tax
#   <chr>                           <dbl>  <dbl>
# 1 Resident tax rates for 2016-17 199401 62962.
# 2 Resident tax rates for 2016-17 199501 63007.
# 3 Resident tax rates for 2016-17 199601 63052.
# 4 Resident tax rates for 2016-17 199701 63097.
# 5 Resident tax rates for 2016-17 199801 63142.
# 6 Resident tax rates for 2016-17 199901 63187.
# 7 Resident tax rates for 2015-16 199401 63277.
# 8 Resident tax rates for 2015-16 199501 63322.
# 9 Resident tax rates for 2015-16 199601 63367.
#10 Resident tax rates for 2015-16 199701 63412.
# … with 194 more rows