How to find the day of the year from dates in R?

To find the day of the year from dates, we can use yday function of lubridate package. For example, if we have a date or a date of vectors then we simply need to pass that date or the vector inside yday function by using the below syntax −
yday(“date”)
or
yday(“vector_of_date”)
Loading lubridate package −
library(lubridate)
date1<-"2020-01-01"
yday(date1)
[1] 1
date2<-"2020-01-25"
yday(date2)
[1] 25
date3<-c("2020-01-25","2020-01-15","2020-02-25","2020-10-03","2020-02-25","2020-05-15","2020-01-28","2020-01-20","2020-11-25","2020-12-25","2020-01-05","2020-06-21","2020-06-22","2020-02-20","2020-03-18","2020-04-19","2020-04-04","2020-04-29","2020-01-03","2020-01-17","2020-11-05","2020-09-09","2020-10-09","2020-04-14","2020-10-02","2020-12-03","2020-11-07","2020-08-15","2020-07-22","2020-07-25","2020-08-25","2020-05-07","2020-05-23","2020-04-01","2020-04-30","2020-07-15","2020-08-17","2020-09-12","2020-10-03","2020-11-16","2020-01-11","2020-06-06","2020-07-24")
date3
[1] "2020-01-25" "2020-01-15" "2020-02-25" "2020-10-03" "2020-02-25"
[6] "2020-05-15" "2020-01-28" "2020-01-20" "2020-11-25" "2020-12-25"
[11] "2020-01-05" "2020-06-21" "2020-06-22" "2020-02-20" "2020-03-18"
[16] "2020-04-19" "2020-04-04" "2020-04-29" "2020-01-03" "2020-01-17"
[21] "2020-11-05" "2020-09-09" "2020-10-09" "2020-04-14" "2020-10-02"
[26] "2020-12-03" "2020-11-07" "2020-08-15" "2020-07-22" "2020-07-25"
[31] "2020-08-25" "2020-05-07" "2020-05-23" "2020-04-01" "2020-04-30"
[36] "2020-07-15" "2020-08-17" "2020-09-12" "2020-10-03" "2020-11-16"
[41] "2020-01-11" "2020-06-06" "2020-07-24" 
yday(date3)
[1] 25 15 56 277 56 136 28 20 330 360 5 173 174 51 78 110 95 120 3
[20] 17 310 253 283 105 276 338 312 228 204 207 238 128 144 92 121 197 230 256
[39] 277 321 11 158 206
date4<-seq(as.Date("2020-01-01"),as.Date("2020-04-01"),by="days")
date4
[1] "2020-01-01" "2020-01-02" "2020-01-03" "2020-01-04" "2020-01-05"
[6] "2020-01-06" "2020-01-07" "2020-01-08" "2020-01-09" "2020-01-10"
[11] "2020-01-11" "2020-01-12" "2020-01-13" "2020-01-14" "2020-01-15"
[16] "2020-01-16" "2020-01-17" "2020-01-18" "2020-01-19" "2020-01-20"
[21] "2020-01-21" "2020-01-22" "2020-01-23" "2020-01-24" "2020-01-25"
[26] "2020-01-26" "2020-01-27" "2020-01-28" "2020-01-29" "2020-01-30"
[31] "2020-01-31" "2020-02-01" "2020-02-02" "2020-02-03" "2020-02-04"
[36] "2020-02-05" "2020-02-06" "2020-02-07" "2020-02-08" "2020-02-09"
[41] "2020-02-10" "2020-02-11" "2020-02-12" "2020-02-13" "2020-02-14"
[46] "2020-02-15" "2020-02-16" "2020-02-17" "2020-02-18" "2020-02-19"
[51] "2020-02-20" "2020-02-21" "2020-02-22" "2020-02-23" "2020-02-24"
[56] "2020-02-25" "2020-02-26" "2020-02-27" "2020-02-28" "2020-02-29"
[61] "2020-03-01" "2020-03-02" "2020-03-03" "2020-03-04" "2020-03-05"
[66] "2020-03-06" "2020-03-07" "2020-03-08" "2020-03-09" "2020-03-10"
[71] "2020-03-11" "2020-03-12" "2020-03-13" "2020-03-14" "2020-03-15"
[76] "2020-03-16" "2020-03-17" "2020-03-18" "2020-03-19" "2020-03-20"
[81] "2020-03-21" "2020-03-22" "2020-03-23" "2020-03-24" "2020-03-25"
[86] "2020-03-26" "2020-03-27" "2020-03-28" "2020-03-29" "2020-03-30"
[91] "2020-03-31" "2020-04-01"
yday(date4)
[1] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
[26] 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
[51] 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75
[76] 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92
date5<-seq(as.Date("2020-01-01"),as.Date("2020-06-01"),by="2 days")
date5
[1] "2020-01-01" "2020-01-03" "2020-01-05" "2020-01-07" "2020-01-09"
[6] "2020-01-11" "2020-01-13" "2020-01-15" "2020-01-17" "2020-01-19"
[11] "2020-01-21" "2020-01-23" "2020-01-25" "2020-01-27" "2020-01-29"
[16] "2020-01-31" "2020-02-02" "2020-02-04" "2020-02-06" "2020-02-08"
[21] "2020-02-10" "2020-02-12" "2020-02-14" "2020-02-16" "2020-02-18"
[26] "2020-02-20" "2020-02-22" "2020-02-24" "2020-02-26" "2020-02-28"
[31] "2020-03-01" "2020-03-03" "2020-03-05" "2020-03-07" "2020-03-09"
[36] "2020-03-11" "2020-03-13" "2020-03-15" "2020-03-17" "2020-03-19"
[41] "2020-03-21" "2020-03-23" "2020-03-25" "2020-03-27" "2020-03-29"
[46] "2020-03-31" "2020-04-02" "2020-04-04" "2020-04-06" "2020-04-08"
[51] "2020-04-10" "2020-04-12" "2020-04-14" "2020-04-16" "2020-04-18"
[56] "2020-04-20" "2020-04-22" "2020-04-24" "2020-04-26" "2020-04-28"
[61] "2020-04-30" "2020-05-02" "2020-05-04" "2020-05-06" "2020-05-08"
[66] "2020-05-10" "2020-05-12" "2020-05-14" "2020-05-16" "2020-05-18"
[71] "2020-05-20" "2020-05-22" "2020-05-24" "2020-05-26" "2020-05-28"
[76] "2020-05-30" "2020-06-01"
yday(date5)
[1] 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37
[20] 39 41 43 45 47 49 51 53 55 57 59 61 63 65 67 69 71 73 75
[39] 77 79 81 83 85 87 89 91 93 95 97 99 101 103 105 107 109 111 113
[58] 115 117 119 121 123 125 127 129 131 133 135 137 139 141 143 145 147 149 151
[77] 153