Question

我想创建一个表或一个新的数据框，以显示原始数据框中每一行的特定值在另一个特定值之前的次数。例如，如果我具有以下数据框：

05-30 13:08:54.297  6116  6180 I ReactNativeJS: 'socket id in App.js : ', undefined
05-30 13:08:54.327  6116  6180 I ReactNativeJS: 'In App.js, token retrieved is : ', undefined
05-30 13:08:54.908  6116  6180 I ReactNativeJS: Running application "emps_app" with appParams: {"rootTag":1}. __DEV__ === true, development-level warning are ON, performance optimizations are OFF
05-30 13:08:55.167  6116  6180 I ReactNativeJS: In Splashscreen DidMount
05-30 13:08:55.308  6116  6180 I ReactNativeJS: 'SplashScreen token result is : ', ''
05-30 13:08:55.309  6116  6180 I ReactNativeJS: Splashscreen result is nothing
05-30 13:08:55.366  6116  6180 I ReactNativeJS: 'After retrieve in spliashscreen : ', { user: null, result: null, success: true }

我想知道每种颜色（红色，蓝色和绿色）出现“ b”，“ a”序列的次数（即，序列中b在a之前的次数）。

正确的答案如下：

x <- data.frame("Red" = c("a", "b", "a", "a", "c", "d"), "Blue" = c("b", "a", "b", "a", "b", "a"), "Green" = c("a", "a", "b", "a", "b", "a"))

Answer 1

这是使用stringr

的一种解决方案

library(stringr)

count_pair <- function(x, pattern) {
   p <- paste(pattern, collapse = "")
   s <- paste(x, collapse = "")
   str_count(s, pattern = p)
}

z <- apply(x, 2, count_pair, pattern = c("b", "a"))
# Red  Blue Green 
# 1     3     2 

# if you want the output in form of a data.frame you could run:
df <- as.data.frame(as.table(z))

#    Var1 Freq
# 1   Red    1
# 2  Blue    3
# 3 Green    2

计算数据帧中每列一个特定值跟随另一个特定值的次数

1 个答案: