python中的管道函数_管道函数(%>%)很简单

符号%>%，这是管道操作，其意思是将%>%左边的对象传递给右边的函数，作为第一个选项的设置(或剩下唯一一个选项的设置)

x %>%f(y) 等同于 f(x, y)

y %>%f(x, ., z) 等同于 f(x, y, z )

直接上栗子🌰：

library(data.table)library(tidyr)

# 先虚构一数据框

set.seed(1)

date

hour

min

second

event

data

head(data)[0:2]

## date hour min second event

## 1: 2016-11-01 7 30 29 u

## 2: 2016-11-02 9 43 36 a

typeof(data)

## [1] "list"

------------------------------------------管道函数(%>%)很简单-------------------------

# 把date，hour，min和second列合并为新列datetime

# R中的日期时间格式为"Year-Month-Day-Hour:Min:Second"

#(一)(%>%) 合着写

dataNew %unite(datehour, date, hour, sep = ' ') %>%unite(datetime, datehour, min, second, sep = ':')

dataNew

## datetime event

## 1: 2016-11-01 7:30:29 u

## 2: 2016-11-02 9:43:36 a

## 3: 2016-11-03 13:58:60 l

## 4: 2016-11-04 20:22:11 q

## 5: 2016-11-05 5:44:47 p

## 6: 2016-11-06 18:52:37 k

## 7: 2016-11-07 19:12:43 r

## 8: 2016-11-08 12:35:6 i

## 9: 2016-11-09 11:7:38 e

## 10: 2016-11-10 1:14:21 b

## 11: 2016-11-11 3:20:42 w

## 12: 2016-11-12 14:1:32 t

## 13: 2016-11-13 23:19:52 h

## 14: 2016-11-14 21:41:26 s

## 15: 2016-11-15 8:16:25 o

# #(二)(%>%) 分步写

dataNew %unite(datehour, date, hour, sep = ' '); dataNew

## datehour min second event

## 1: 2016-11-01 7 30 29 u

## 2: 2016-11-02 9 43 36 a

## 3: 2016-11-03 13 58 60 l

## 4: 2016-11-04 20 22 11 q

## 5: 2016-11-05 5 44 47 p

## 6: 2016-11-06 18 52 37 k

## 7: 2016-11-07 19 12 43 r

## 8: 2016-11-08 12 35 6 i

## 9: 2016-11-09 11 7 38 e

## 10: 2016-11-10 1 14 21 b

## 11: 2016-11-11 3 20 42 w

## 12: 2016-11-12 14 1 32 t

## 13: 2016-11-13 23 19 52 h

## 14: 2016-11-14 21 41 26 s

## 15: 2016-11-15 8 16 25 o

dataNew %>% unite(datetime, datehour, min, second, sep = ':')

## datetime event

## 1: 2016-11-01 7:30:29 u

## 2: 2016-11-02 9:43:36 a

## 3: 2016-11-03 13:58:60 l

## 4: 2016-11-04 20:22:11 q

## 5: 2016-11-05 5:44:47 p

## 6: 2016-11-06 18:52:37 k

## 7: 2016-11-07 19:12:43 r

## 8: 2016-11-08 12:35:6 i

## 9: 2016-11-09 11:7:38 e

## 10: 2016-11-10 1:14:21 b

## 11: 2016-11-11 3:20:42 w

## 12: 2016-11-12 14:1:32 t

## 13: 2016-11-13 23:19:52 h

## 14: 2016-11-14 21:41:26 s

## 15: 2016-11-15 8:16:25 o

# #(三)不用％>％也能写

dt

dt

## datehour min second event

## 1: 2016-11-01 7 30 29 u

## 2: 2016-11-02 9 43 36 a

## 3: 2016-11-03 13 58 60 l

## 4: 2016-11-04 20 22 11 q

## 5: 2016-11-05 5 44 47 p

## 6: 2016-11-06 18 52 37 k

## 7: 2016-11-07 19 12 43 r

## 8: 2016-11-08 12 35 6 i

## 9: 2016-11-09 11 7 38 e

## 10: 2016-11-10 1 14 21 b

## 11: 2016-11-11 3 20 42 w

## 12: 2016-11-12 14 1 32 t

## 13: 2016-11-13 23 19 52 h

## 14: 2016-11-14 21 41 26 s

## 15: 2016-11-15 8 16 25 o

dt2

dt2

## datatime event

## 1: 2016-11-01 7:30:29 u

## 2: 2016-11-02 9:43:36 a

## 3: 2016-11-03 13:58:60 l

## 4: 2016-11-04 20:22:11 q

## 5: 2016-11-05 5:44:47 p

## 6: 2016-11-06 18:52:37 k

## 7: 2016-11-07 19:12:43 r

## 8: 2016-11-08 12:35:6 i

## 9: 2016-11-09 11:7:38 e

## 10: 2016-11-10 1:14:21 b

## 11: 2016-11-11 3:20:42 w

## 12: 2016-11-12 14:1:32 t

## 13: 2016-11-13 23:19:52 h

## 14: 2016-11-14 21:41:26 s

## 15: 2016-11-15 8:16:25 o