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Patrick Giraudoux

2021-Feb-22 15:15 UTC

[R] strptime, date and conversion of week number into POSIX

Sorry to answer to myself, but the format was clearly incorrect in the 
previous post. It should read, refering to the 1th day of the week:

strptime(paste0(mydate,"-1"),format="%Y-%W-%u")

It converts better, but with a NA on week 53
> strptime(paste0(pays$year_week,"-1"),format="%Y-%W-%u")  [1] "2020-01-06 CET"  "2020-01-13 CET"  "2020-01-20
CET"  "2020-01-27 CET"
  [5] "2020-02-03 CET"  "2020-02-10 CET"  "2020-02-17
CET"  "2020-02-24 CET"
  [9] "2020-03-02 CET"  "2020-03-09 CET"  "2020-03-16
CET"  "2020-03-23 CET"
[13] "2020-03-30 CEST" "2020-04-06 CEST" "2020-04-13
CEST" "2020-04-20 CEST"
[17] "2020-04-27 CEST" "2020-05-04 CEST" "2020-05-11
CEST" "2020-05-18 CEST"
[21] "2020-05-25 CEST" "2020-06-01 CEST" "2020-06-08
CEST" "2020-06-15 CEST"
[25] "2020-06-22 CEST" "2020-06-29 CEST" "2020-07-06
CEST" "2020-07-13 CEST"
[29] "2020-07-20 CEST" "2020-07-27 CEST" "2020-08-03
CEST" "2020-08-10 CEST"
[33] "2020-08-17 CEST" "2020-08-24 CEST" "2020-08-31
CEST" "2020-09-07 CEST"
[37] "2020-09-14 CEST" "2020-09-21 CEST" "2020-09-28
CEST" "2020-10-05 CEST"
[41] "2020-10-12 CEST" "2020-10-19 CEST" "2020-10-26
CET"  "2020-11-02 CET"
[45] "2020-11-09 CET"  "2020-11-16 CET"  "2020-11-23
CET"  "2020-11-30 CET"
[49] "2020-12-07 CET"  "2020-12-14 CET"  "2020-12-21
CET"  "2020-12-28 CET"
[53] NA                "2021-01-04 CET"  "2021-01-11 CET" 
"2021-01-18 CET"
[57] "2021-01-25 CET"  "2021-02-01 CET"  "2021-02-08
CET"
Warning message:
In strptime(paste0(pays$year_week, "-1"), format =
"%Y-%W-%u") :
   (0-based) yday 369 in year 2020 is invalid


Any idea on how to handle this ?




Le 22/02/2021 ? 15:26, Patrick Giraudoux a ?crit?:>
> Dear all,
>
> I have a trouble trying to convert dates? given in character to POSIX. 
> The date is expressed as a year then the week number e.g.
"2020-01"
> (first week of 2020). I thought is can be converted as following:
>
> strptime(mydate,format="%Y-%W")
>
> %W refering to the week of the year as decimal number (00?53) using 
> Monday as the first day of week (and typically with the first Monday 
> of the year as day 1 of week 1), as indicated in the doc.
>
> However, I got this result, with the month fixed to 02 (february) and 
> day 22 (only the year is? converted correctly):
>
> strptime(mydate,format="%Y-%W") [1] "2020-02-22 CET"
"2020-02-22 CET"
> "2020-02-22 CET" "2020-02-22 CET" [5] "2020-02-22
CET" "2020-02-22
> CET" "2020-02-22 CET" "2020-02-22 CET" [9]
"2020-02-22 CET"
> "2020-02-22 CET" "2020-02-22 CET" "2020-02-22
CET" [13] "2020-02-22
> CET" "2020-02-22 CET" "2020-02-22 CET"
"2020-02-22 CET" [17]
> "2020-02-22 CET" "2020-02-22 CET" "2020-02-22
CET" "2020-02-22 CET"
> [21] "2020-02-22 CET" "2020-02-22 CET" "2020-02-22
CET" "2020-02-22
> CET" [25] "2020-02-22 CET" "2020-02-22 CET"
"2020-02-22 CET"
> "2020-02-22 CET" [29] "2020-02-22 CET" "2020-02-22
CET" "2020-02-22
> CET" "2020-02-22 CET" [33] "2020-02-22 CET"
"2020-02-22 CET"
> "2020-02-22 CET" "2020-02-22 CET" [37] "2020-02-22
CET" "2020-02-22
> CET" "2020-02-22 CET" "2020-02-22 CET" [41]
"2020-02-22 CET"
> "2020-02-22 CET" "2020-02-22 CET" "2020-02-22
CET" [45] "2020-02-22
> CET" "2020-02-22 CET" "2020-02-22 CET"
"2020-02-22 CET" [49]
> "2020-02-22 CET" "2020-02-22 CET" "2020-02-22
CET" "2020-02-22 CET"
> [53] "2020-02-22 CET" "2021-02-22 CET" "2021-02-22
CET" "2021-02-22
> CET" [57] "2021-02-22 CET" "2021-02-22 CET"
"2021-02-22 CET"
>
> You'll find below a dump of "mydate" you can copy and paster
if you
> need a try
>
> Any hint welcome...
>
> Best,
>
> Patrick
>
> mydate <-
> c("2020-01", "2020-02", "2020-03",
"2020-04", "2020-05", "2020-06",
> "2020-07", "2020-08", "2020-09",
"2020-10", "2020-11", "2020-12",
> "2020-13", "2020-14", "2020-15",
"2020-16", "2020-17", "2020-18",
> "2020-19", "2020-20", "2020-21",
"2020-22", "2020-23", "2020-24",
> "2020-25", "2020-26", "2020-27",
"2020-28", "2020-29", "2020-30",
> "2020-31", "2020-32", "2020-33",
"2020-34", "2020-35", "2020-36",
> "2020-37", "2020-38", "2020-39",
"2020-40", "2020-41", "2020-42",
> "2020-43", "2020-44", "2020-45",
"2020-46", "2020-47", "2020-48",
> "2020-49", "2020-50", "2020-51",
"2020-52", "2020-53", "2021-01",
> "2021-02", "2021-03", "2021-04",
"2021-05", "2021-06")
>

	[[alternative HTML version deleted]]

Uwe Ligges

2021-Feb-22 16:09 UTC

head link

[R] strptime, date and conversion of week number into POSIX

That monday does not exist. FOr the week before:

strptime(paste0("2020-52","-1"),format="%Y-%W-%u")
[1] "2020-12-28"

One week later is no longer in 2020, so there is no 53th week.

Best,
Uwe Ligges





On 22.02.2021 16:15, Patrick Giraudoux wrote:> Sorry to answer to myself, but the format was clearly incorrect in the
> previous post. It should read, refering to the 1th day of the week:
> 
> strptime(paste0(mydate,"-1"),format="%Y-%W-%u")
> 
> It converts better, but with a NA on week 53
> 
>>
strptime(paste0(pays$year_week,"-1"),format="%Y-%W-%u")
>    [1] "2020-01-06 CET"  "2020-01-13 CET" 
"2020-01-20 CET"  "2020-01-27 CET"
>    [5] "2020-02-03 CET"  "2020-02-10 CET" 
"2020-02-17 CET"  "2020-02-24 CET"
>    [9] "2020-03-02 CET"  "2020-03-09 CET" 
"2020-03-16 CET"  "2020-03-23 CET"
> [13] "2020-03-30 CEST" "2020-04-06 CEST"
"2020-04-13 CEST" "2020-04-20 CEST"
> [17] "2020-04-27 CEST" "2020-05-04 CEST"
"2020-05-11 CEST" "2020-05-18 CEST"
> [21] "2020-05-25 CEST" "2020-06-01 CEST"
"2020-06-08 CEST" "2020-06-15 CEST"
> [25] "2020-06-22 CEST" "2020-06-29 CEST"
"2020-07-06 CEST" "2020-07-13 CEST"
> [29] "2020-07-20 CEST" "2020-07-27 CEST"
"2020-08-03 CEST" "2020-08-10 CEST"
> [33] "2020-08-17 CEST" "2020-08-24 CEST"
"2020-08-31 CEST" "2020-09-07 CEST"
> [37] "2020-09-14 CEST" "2020-09-21 CEST"
"2020-09-28 CEST" "2020-10-05 CEST"
> [41] "2020-10-12 CEST" "2020-10-19 CEST"
"2020-10-26 CET"  "2020-11-02 CET"
> [45] "2020-11-09 CET"  "2020-11-16 CET" 
"2020-11-23 CET"  "2020-11-30 CET"
> [49] "2020-12-07 CET"  "2020-12-14 CET" 
"2020-12-21 CET"  "2020-12-28 CET"
> [53] NA                "2021-01-04 CET"  "2021-01-11
CET"  "2021-01-18 CET"
> [57] "2021-01-25 CET"  "2021-02-01 CET" 
"2021-02-08 CET"
> Warning message:
> In strptime(paste0(pays$year_week, "-1"), format =
"%Y-%W-%u") :
>     (0-based) yday 369 in year 2020 is invalid
> 
> 
> Any idea on how to handle this ?
> 
> 
> 
> 
> Le 22/02/2021 ? 15:26, Patrick Giraudoux a ?crit?:
>>
>> Dear all,
>>
>> I have a trouble trying to convert dates? given in character to POSIX.
>> The date is expressed as a year then the week number e.g.
"2020-01"
>> (first week of 2020). I thought is can be converted as following:
>>
>> strptime(mydate,format="%Y-%W")
>>
>> %W refering to the week of the year as decimal number (00?53) using
>> Monday as the first day of week (and typically with the first Monday
>> of the year as day 1 of week 1), as indicated in the doc.
>>
>> However, I got this result, with the month fixed to 02 (february) and
>> day 22 (only the year is? converted correctly):
>>
>> strptime(mydate,format="%Y-%W") [1] "2020-02-22
CET" "2020-02-22 CET"
>> "2020-02-22 CET" "2020-02-22 CET" [5]
"2020-02-22 CET" "2020-02-22
>> CET" "2020-02-22 CET" "2020-02-22 CET" [9]
"2020-02-22 CET"
>> "2020-02-22 CET" "2020-02-22 CET" "2020-02-22
CET" [13] "2020-02-22
>> CET" "2020-02-22 CET" "2020-02-22 CET"
"2020-02-22 CET" [17]
>> "2020-02-22 CET" "2020-02-22 CET" "2020-02-22
CET" "2020-02-22 CET"
>> [21] "2020-02-22 CET" "2020-02-22 CET"
"2020-02-22 CET" "2020-02-22
>> CET" [25] "2020-02-22 CET" "2020-02-22 CET"
"2020-02-22 CET"
>> "2020-02-22 CET" [29] "2020-02-22 CET"
"2020-02-22 CET" "2020-02-22
>> CET" "2020-02-22 CET" [33] "2020-02-22 CET"
"2020-02-22 CET"
>> "2020-02-22 CET" "2020-02-22 CET" [37]
"2020-02-22 CET" "2020-02-22
>> CET" "2020-02-22 CET" "2020-02-22 CET" [41]
"2020-02-22 CET"
>> "2020-02-22 CET" "2020-02-22 CET" "2020-02-22
CET" [45] "2020-02-22
>> CET" "2020-02-22 CET" "2020-02-22 CET"
"2020-02-22 CET" [49]
>> "2020-02-22 CET" "2020-02-22 CET" "2020-02-22
CET" "2020-02-22 CET"
>> [53] "2020-02-22 CET" "2021-02-22 CET"
"2021-02-22 CET" "2021-02-22
>> CET" [57] "2021-02-22 CET" "2021-02-22 CET"
"2021-02-22 CET"
>>
>> You'll find below a dump of "mydate" you can copy and
paster if you
>> need a try
>>
>> Any hint welcome...
>>
>> Best,
>>
>> Patrick
>>
>> mydate <-
>> c("2020-01", "2020-02", "2020-03",
"2020-04", "2020-05", "2020-06",
>> "2020-07", "2020-08", "2020-09",
"2020-10", "2020-11", "2020-12",
>> "2020-13", "2020-14", "2020-15",
"2020-16", "2020-17", "2020-18",
>> "2020-19", "2020-20", "2020-21",
"2020-22", "2020-23", "2020-24",
>> "2020-25", "2020-26", "2020-27",
"2020-28", "2020-29", "2020-30",
>> "2020-31", "2020-32", "2020-33",
"2020-34", "2020-35", "2020-36",
>> "2020-37", "2020-38", "2020-39",
"2020-40", "2020-41", "2020-42",
>> "2020-43", "2020-44", "2020-45",
"2020-46", "2020-47", "2020-48",
>> "2020-49", "2020-50", "2020-51",
"2020-52", "2020-53", "2021-01",
>> "2021-02", "2021-03", "2021-04",
"2021-05", "2021-06")
>>
> 
> 
> 	[[alternative HTML version deleted]]
> 
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R help - Feb 2021 - strptime, date and conversion of week number into POSIX

[R] strptime, date and conversion of week number into POSIX

[R] strptime, date and conversion of week number into POSIX