I am trying to use the Zoo package to read in daily observations which do not occur on each day. The date format looks like this, and it is in the first column of dataset: 25-May-07 The command I use is: z <- read.zoo("multiplier7.csv", sep = ";", header = TRUE, format="%d-%b-%y") I get this error: Error in strptime(x, format, tz = "GMT") : input string is too long First question is: 1. Is Zoo the right package to use if I want to use lm regression with a spline time dummy? The bs command does not work because I need to convert it into a time series. 2. Why is this error occurring and how to fix?