Styjun

I am new to R and need help in the following.
I have this data:

 Time Temperature
 4.460672 96.32332
 15.542545 96.32332
 16.750386 96.32332
 38.709795 96.32332
 39.952442 96.32332
 41.320898 96.32332
 55.375259 96.32332
 61.855321 100.47791
 66.464590 100.47791
 66.966965 100.47791
 76.100513 100.47791
 76.617365 100.47791
 77.186545 100.47791
 83.032157 100.47791
 87.772441 100.47791
 91.786988 100.47791
 98.161933 100.47791
101.258411 100.47791
105.186097 100.47791
105.928643 100.47791
111.476967 100.47791
119.426046 100.47791
124.406232 92.70218
135.352858 92.70218
136.545958 92.70218

I need to create a dataframe ‘minute_data’. Each row corresponds to one minute of observations, it contains count of events during that minute and the temperature.

Some minutes may not contain any events. Rows corresponding to such minutes should be excluded from the dataframe.

The dataframe should look like (first 2 rows):

minute count temperature
 1 7 96.32332
 2 15 100.47791

You can use dplyr for this:

library(dplyr)
df %>%
 mutate(minute = Time %/% 60 + 1) %>%
 group_by(minute) %>%
 summarise(count = n(),
 temperature = first(temperature)) %>%
 select(-Time)

Note: Change first to mean if you want mean

And (of course) data.table can also perform this operation

sample data

library( data.table )
DT <- fread("Time Temperature
4.460672 96.32332
15.542545 96.32332
16.750386 96.32332
38.709795 96.32332
39.952442 96.32332
41.320898 96.32332
55.375259 96.32332
61.855321 100.47791
66.464590 100.47791
66.966965 100.47791
76.100513 100.47791
76.617365 100.47791
77.186545 100.47791
83.032157 100.47791
87.772441 100.47791
91.786988 100.47791
98.161933 100.47791
101.258411 100.47791
105.186097 100.47791
105.928643 100.47791
111.476967 100.47791
119.426046 100.47791
124.406232 92.70218
135.352858 92.70218
136.545958 92.70218")

code

It is actually a one-liner, but for readability I added some linebreaks.

DT[, list( count = .N, 
 temperature = mean( Temperature ) ), 
 by = .( minute = floor( Time / 60 ) + 1 )]

output

# minute count temperature
# 1: 1 7 96.32332
# 2: 2 15 100.47791
# 3: 3 3 92.70218