search for: julianday

Hello, I am having a problem making use of some data outputted from an instrument in a somewhat weird format. The instrument outputs two columns - one called JulianDay.Hour and one called Minutes.Seconds. I would like to convert these columns into a single column with a time. So I was using substr() and paste to extract that info. This works fine for the JulianDay.Hour column as there are always five characters in an entry. However in the Minutes.Seconds column a...

...ily measurements of river flow. I would like to create a "ts" object from this data. Here's a sample data set: date <- as.Date(c(1:300), format="%Y") year=as.numeric(format(date, format = "%Y")) month=as.numeric(format(date, format = "%m")) julianday=as.numeric(format(date, format = "%j")) week=floor(julianday/7) flow <- sin(2*pi/53*c(1:300)) data <- cbind.data.frame(date,year,month,julianday,week, flow) I know how to do this with exact dates using the irts package: install.packages("tseries") library(tseries)...

...uot;SELECT e.*, c.DATE 'DATEctrl', c.TIME 'TIMEctrl', c.PRICE 'PRICEctrl', c.SIZE 'SIZEctrl' FROM edt e, ctq c WHERE e.SYMBOL = c.SYMBOL AND julianday(e.DATE) - julianday(c.DATE) BETWEEN 15 AND 75 AND strftime('%H:%M:%S',c.TIME) BETWEEN strftime('%H:%M:%S',e.BEGTIME) AND strftime('%H:%M:%S',e.ENDTIME)") [[alternative HTML version deleted]]

...in advance for your patience and help with a complete novice! I am working with a large multivariate data set that has 10 explanatory environmental variables (e.g. temp, depth) and over 60 response variables (each is a separate species). My data frame is set up like the simplified version below: JulianDay Temperature Salinity Depth Copepod Barnacle Gastropod Bivalve 222 12.1 33 0.3 500 756 0 178 222 12.3 33.2 1.1 145 111 0...

I am working on a simple pilot project comparing the capability of SQL, SAS and R to perform a rolling mean per the following instructions. I have completed the SQL and SAS analysis, so now it's R's turn. Calculate mean values of x (x=count) for each date in the dataset where mean = the average count of days [t-9] through day [t-3] for each date/illness combination. Dataset aggpilot

Necesito algo de programación básica para resolver un problema, un inconveniente es que intente "if", cuándo se lo aplico digamos a x <- 5 no hay drama, pero si es a leche$litros me dice que solo se toma el primer elemento. Como pueden ver estoy re perdido. Mi problema: los datos están en un data.frame como el siguiente animal inicio fin control idlactancias