如何將行值更改為列名 (R) (How change Row values to Column names (R))

問題描述

如何將行值更改為列名 (R) (How change Row values to Column names (R))

我正在處理 COVID19 數據。有一個不便之處。我有一個名為 location 的列，所有國家都在該列下。為了說明，第一個值是國家 A、日期 A、下一個國家 A、日期 B...國家 Z、日期 Z。我想知道如何按日期對所有值進行分組並將每個國家作為單獨的列？

這是數據的鏈接：

https://ourworldindata .org/coronavirus‑source‑data

參考解法

方法 1:

You can reshape the data using code like the following:

df_example = with(df, data.frame(location = location,
                                date = date, 
                                new_cases = new_cases))

df_example = reshape(df_example, timevar = "location", idvar = "date", direction = "wide")
df_example = df_example[order(df_example$date), ]

Note here that I kept only one variable as the cell value in the new data frame (i.e., new_cases), because the new data frame is already very wide (it has 213 columns now). If you keep additional variables the new data frame will be wider.

head(df_example)   # I will not put the output here, you can try yourself

The following three lines will make the new data frame look nicer.

cnames = names(df_example)[2:ncol(df_example)]
cnames = unlist(lapply(cnames, function(x) substr(x, 11, nchar(x))))
names(df_example)[2:ncol(df_example)] = cnames

(by Tigran Danielyan、Haci Duru)

參考文件

1. How change Row values to Column names (R) (CC BY‑SA 2.5/3.0/4.0)