[英]How do I change the names of columns in multiple dataframes using a mapping file in R?
我有一个循环遍历多年数据的脚本,一次一年。 每一年的数据都由多个数据帧组成,这些数据帧被放置在一个名为all_input
的列表中。 在循环的开始(数据读入之后),我试图在处理的rest之前以相同的格式获取所有年份的数据。
我遇到的问题是列名不统一。 我想保留的每个 dataframe 中包含 5 列,我希望它们被称为total_emissions
uom
tribal_name
st_usps_cd
和description
。 在某些数据框中,它们已经具有这些名称,而在另一些数据框中,它们具有各种名称,例如pollutant.desc
或pollutant_desc
。
我目前的做法是这样的:
# Create a mapping file for the column names
header_map <- data.frame(orignal_col = c( "pollutant_desc", "pollutant.desc", "emissions.uom", "total.emissions", "tribal.name", "state" ),
new_col = c( "description", "description", "uom", "total_emissions", "tribal_name", "st_usps_cd" ), stringsAsFactors = FALSE)
# change the column names
lapply(all_input, function(x) {
names(x)[match(header_map$orignal_col, names(x))] <- header_map$new_col
x
}) -> all_input
这将创建一个 header 映射文件,如下所示:
original_col new_col
pollutant_desc description
pollutant.desc description
emissions.uom uom
total.emissions total_emissions
tribal.name tribal_name
state st_usps_cd
我得到的错误如下:
Error in names(x)[match(header_map$orignal_col, names(x))] <- header_map$new_col :
NAs are not allowed in subscripted assignments
我知道,因为处理具有不同列名的新年份数据时,我必须手动将条目添加到 header 文件中,但是我怎样才能让它工作呢?
假样本数据。 df1 和 df2 代表“2017”数据的格式,其中多列需要更改名称,但当前名称在数据帧之间保持一致。 df3 表示“2011”数据,其中所有列名都应如此。 df4 代表“2014”数据,其中唯一需要更改的列是pollutant_desc
。 请注意,每个 dataframe 中都有多余的列是不需要的,可以忽略。 提醒一下,这些数据帧并不是同时读取的。 循环按年份进行,因此 df1 和 df2 (在列表all_input
中)将被格式化和处理。 然后删除所有数据,并使用未来几年的数据框创建一个新的all_input
列表,这些数据框将具有不同的列名。 代码必须在不改变的情况下使用多年。
> dput(df1)
structure(list(total.emissions = structure(1:2, .Label = c("100",
"300"), class = "factor"), emissions.uom = structure(1:2, .Label = c("LB",
"TON"), class = "factor"), international = c(TRUE, TRUE), hours = structure(2:1, .Label = c("17",
"3"), class = "factor"), tribal.name = structure(2:1, .Label = c("FLLK",
"SUWJG"), class = "factor"), state = structure(1:2, .Label = c("AK",
"MN"), class = "factor"), pollutant.desc = structure(1:2, .Label = c("Methane",
"NO2"), class = "factor"), policy = c(TRUE, FALSE)), class = "data.frame", row.names = c(NA,
-2L))
> dput(df2)
structure(list(total.emissions = structure(2:1, .Label = c("20",
"400"), class = "factor"), emissions.uom = structure(c(1L, 1L
), .Label = "TON", class = "factor"), international = c(FALSE,
TRUE), hours = structure(2:1, .Label = c("1", "8"), class = "factor"),
tribal.name = structure(2:1, .Label = c("SOSD", "WMFJU"), class = "factor"),
state = structure(2:1, .Label = c("SD", "WY"), class = "factor"),
pollutant.desc = structure(1:2, .Label = c("CO2", "SO2"), class = "factor"),
policy = c(FALSE, FALSE)), class = "data.frame", row.names = c(NA,
-2L))
> dput(df3)
structure(list(total_emissions = structure(2:1, .Label = c("200",
"30"), class = "factor"), uom = structure(c(1L, 1L), .Label = "TON", class = "factor"),
boundaries = structure(2:1, .Label = c("N", "Y"), class = "factor"),
tribal_name = structure(2:1, .Label = c("SOSD", "WMFJU"), class = "factor"),
st_usps_cd = structure(2:1, .Label = c("ID", "KS"), class = "factor"),
description = structure(c(1L, 1L), .Label = "SO2", class = "factor"),
policy = c(FALSE, TRUE), time = structure(1:2, .Label = c("17",
"7"), class = "factor")), class = "data.frame", row.names = c(NA,
-2L))
> dput(df4)
structure(list(total_emissions = structure(2:1, .Label = c("700",
"75"), class = "factor"), uom = structure(c(1L, 1L), .Label = "LB", class = "factor"),
tribal_name = structure(1:2, .Label = c("SSJY", "WNCOPS"), class = "factor"),
st_usps_cd = structure(1:2, .Label = c("MO", "NY"), class = "factor"),
pollutant_desc = structure(2:1, .Label = c("CO2", "Methane"
), class = "factor"), boundaries = structure(c(1L, 1L), .Label = "N", class = "factor"),
policy = c(FALSE, FALSE), time = structure(1:2, .Label = c("2",
"3"), class = "factor")), class = "data.frame", row.names = c(NA,
-2L))
谢谢!
尝试这个:
list_of_frames1 <- list(df1, df2, df3, df4)
list_of_frames2 <- lapply(list_of_frames1, function(x) {
nms <- intersect(names(x), header_map$orignal_col)
names(x)[ match(nms, names(x)) ] <- header_map$new_col[ match(nms, header_map$orignal_col) ]
x
})
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