strptime

问题 strptime() function in C fails to detect invalid dates. Ex: 2011-02-31 , 2011-04-31. Is there any other function or workaround to this problem 回答1: You can use mktime to normalize your structure after using strptime . struct tm ltm = {0}; char buf[] = "2011-02-31"; puts(buf); strptime(buf, "%Y-%m-%d", &ltm); mktime(&ltm); strftime(buf, sizeof(buf), "%Y-%m-%d", &ltm); puts(buf); The example above will produce the output below: 2011-02-31 2011-03-03 If the strings before and after mktime do not

问题 I am trying to extract out the time from a character string in R and can't stop getting NA as a result. I have tried numerous variations of the regular expression tags, but can't seem to get around this simple problem. Any help/clarifications are appreciated. Here is my code for an example: > x [1] "2/7/2013 7:43" > class(x) [1] "character" > z <- strptime(x, "%H:%M") > z [1] NA 回答1: R doesn't know that your string is a datetime. So make it one first: y <- strptime(x, format='%m/%d/%Y %H:%M')

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 4 years ago . I'm trying to use strptime to format dates I'm reading in but only get NA values are returned in the output. My raw data is in the format of 1974-01-01, and the length of the dataset is 12049 so the last date is 2006-12-31. The code I use is: Data$date.yyyymmdd <- as.POSIXct(strptime(Data$date.yyyymmdd, format =

问题 I have a variable date with timestamps: 27.03.2016 01:30 27.03.2016 02:00 27.03.2016 02:30 The format is character . After using as.POSIXct(strptime(data.frame$date, format = "%d.%m.%Y %R")) two of the 17568 observations are NA. The others are printed correctly. Why does it happen? 来源： https://stackoverflow.com/questions/42504670/nexpected-na-after-using-as-posixctstrptime

问题 I have a variable date with timestamps: 27.03.2016 01:30 27.03.2016 02:00 27.03.2016 02:30 The format is character . After using as.POSIXct(strptime(data.frame$date, format = "%d.%m.%Y %R")) two of the 17568 observations are NA. The others are printed correctly. Why does it happen? 来源： https://stackoverflow.com/questions/42504670/nexpected-na-after-using-as-posixctstrptime

问题 UPDATE I've managed to load the data of the first 1000000 rows using the following code: newFile <- read.table("course_4_proj_1.txt", header=TRUE, sep=";", na.strings = "?", nrows= 1000000, stringsAsFactors=TRUE) This is what the head() returns, as an FYI head(newFile) Date Time Global_active_power Global_reactive_power Voltage Global_intensity 1 16/12/2006 17:24:00 4.216 0.418 234.84 18.4 2 16/12/2006 17:25:00 5.360 0.436 233.63 23.0 3 16/12/2006 17:26:00 5.374 0.498 233.29 23.0 4 16/12/2006

问题 UPDATE I've managed to load the data of the first 1000000 rows using the following code: newFile <- read.table("course_4_proj_1.txt", header=TRUE, sep=";", na.strings = "?", nrows= 1000000, stringsAsFactors=TRUE) This is what the head() returns, as an FYI head(newFile) Date Time Global_active_power Global_reactive_power Voltage Global_intensity 1 16/12/2006 17:24:00 4.216 0.418 234.84 18.4 2 16/12/2006 17:25:00 5.360 0.436 233.63 23.0 3 16/12/2006 17:26:00 5.374 0.498 233.29 23.0 4 16/12/2006

问题 Hi i have some troubles concerning the strptime() function, i have character data like: data2[,1] 24-feb-15 26-ene-15 29-dic-14 i try to use srtptime() : strptime(data2[,1], "%d-%b-%y") but unfortunately it only works for 24-feb-15, i guess its because the other months are spanish abbreviated, so R doesn't recognize them, i have a lot of observations so i want to find a way to do it without changing manually the name of the months. Thanks for your help. JDaniel 回答1: strptime will recognize

问题 I am new to C. When I practicing C to covert time sting to structure tm back and forth. I noticed some difference. Please advice what I did wrong. #include <string.h> #include <stdio.h> #include <time.h> /* test different format string to strptime " %A, %b %d, %X %z %Y " " %A, %b %d, %X %Z %Y " */ int main(int argc,char *argv[]) { char date[] = "6 Mar 2001 12:33:45"; char fmt[80]; struct tm tm; if (argc==1) return 0; strcpy(fmt,argv[1]); memset(&tm, 0, sizeof(struct tm)); if (strptime(date,"

问题 I'm having trouble finding a way to parse the timezone out of strings like the following: "Thu, 1 Sep 2011 09:06:03 -0400 (EDT)" What I need to do in the larger scheme of my program is take in a char* and convert it to a time_t. The following is a simple test program I wrote to try and figure out if strptime was accounting for timezone at all, and it doesn't appear to be (when this test program executes all the printed numbers are the same when they should differ). Suggestions? I also tried