tidyr: Easily tidy data with spread and gather functions.
Reshape Data
-
gather将多列聚集成键值对(key-value pairs) (reshap2::melt)
gather(data,key, value, ..., na.rm = FALSE, convert = FALSE,factor_key = FALSE)
参数：
key, value: 要聚合成的新key,value列的名字
… : 要gather的列名. （选择x到z的所有列 x:z, 除了y -y）
-
spread 将key扩展成多列，value为要显示的值 (reshap2::dcast)
spread(data, key, value, fill = NA , drop = TRUE,sep = NULL)
说明：
- 若行和key组成的索引不唯一，报错
- sep: If NULL, 列名为变量key的值. If non-NULL, 列名为
<key_name><sep><key_value>
Split or Unit Cells
separate(data, col, into, sep, remove = TRUE) #单列分割成多列
separate_rows(data, ..., sep = "[^[:alnum:].]+", convert = FALSE) #当列分裂成多行
unite(data,col,sep =”_”,remove = TRUE) #多列联合成单列
# 示例
table3 %>%
separate(rate, into = c("cases", "population"), convert = TRUE)
Handle Missing Values
replace_na(data, replace = list() )
drop_na(data)
fill(data, ..., .direction = c("down", "up"))
