Hi,
So, I've got a vector of strings that look like this: ID <- c("IBBS3_MSM_HN01209","IBBS3_MSM_HN01210","IBBS3_MSM_HN01211", "IBBS3_MSM_HN10212","IBBS3_MSM_HN104213","IBBS3_MSM_HN10214", "IBBS3_MSM_HN44215","IBBS3_MSM_HN44216","IBBS3_MSM_HN44217", "IBBS3_MSM_HN44218","IBBS3_MSM_HN44219","IBBS3_MSM_HN44220", "IBBS3_MSM_HN44221","IBBS3_MSM_HN44222","IBBS3_MSM_HN44223", "IBBS3_MSM_HN44224","IBBS3_MSM_HN44225","IBBS3_MSM_HN44226", "IBBS3_MSM_HN44227","IBBS3_MSM_HN12228","IBBS3_MSM_HN12229", "IBBS3_MSM_HN12230","IBBS3_MSM_HN12231","IBBS3_MSM_HN12232", "IBBS3_MSM_HN12233","IBBS3_MSM_HN12234","IBBS3_MSM_HN12235", "IBBS3_MSM_HN12236","IBBS3_MSM_HN12237","IBBS3_MSM_HN12238", "IBBS3_MSM_HN12239","IBBS3_MSM_HN12240","IBBS3_MSM_HN12241", "IBBS3_MSM_HN12242","IBBS3_MSM_HN12243","IBBS3_MSM_HN12244", "IBBS3_MSM_HN12245","IBBS3_MSM_HN12246","IBBS3_MSM_HN12247", "IBBS3_MSM_HN12248","IBBS3_MSM_HN12249","IBBS3_MSM_HN12250", "IBBS3_MSM_HN12251","IBBS3_MSM_HN12252","IBBS3_MSM_HN12253", "IBBS3_MSM_HN12254","IBBS3_MSM_HN12255","IBBS3_MSM_HN25256", "IBBS3_MSM_HN25257","IBBS3_MSM_HN25258","IBBS3_MSM_HN25259", "IBBS3_MSM_HN25260","IBBS3_MSM_HN25261","IBBS3_MSM_HN25262", "IBBS3_MSM_HN25263","IBBS3_MSM_HN25264","IBBS3_MSM_HN25265", "IBBS3_MSM_HN25266","IBBS3_MSM_HN25267","IBBS3_MSM_HN25268", "IBBS3_MSM_HN25269","IBBS3_MSM_HN25270","IBBS3_MSM_HN25271", "IBBS3_MSM_HN25272","IBBS3_MSM_HN25273","IBBS3_MSM_HN25274", "IBBS3_MSM_HN25275","IBBS3_MSM_HN25276", "IBBS3_MSM_HN25277", "IBBS3_MSM_HN25278","IBBS3_MSM_HN25279","IBBS3_MSM_HN25280", "IBBS3_MSM_HN25281","IBBS3_MSM_HN25282","IBBS3_MSM_HN25283", "IBBS3_MSM_HN25284","IBBS3_MSM_HMC44285", "IBBS3_MSM_HMC44286", "IBBS3_MSM_HMC44287","IBBS3_MSM_HMC44288","IBBS3_MSM_HMC44289", "IBBS3_MSM_HMC44290","IBBS3_MSM_HMC44291","IBBS3_MSM_HMC44292", "IBBS3_MSM_HMC44293","IBBS3_MSM_HMC44294","IBBS3_MSM_HMC44295", "IBBS3_MSM_HMC44296","IBBS3_MSM_HMC44297","IBBS3_MSM_HMC44298", "IBBS3_MSM_HMC44299","IBBS3_MSM_HMC44300","IBBS3_MSM_HMC44301", "IBBS3_MSM_HMC44302","IBBS3_MSM_HMC44303","IBBS3_MSM_HMC44304", "IBBS3_MSM_HMC44305","IBBS3_MSM_HMC44306","IBBS3_MSM_HMC44307", "IBBS3_MSM_HMC44309") This is an ID that is in the following format: IBBS3_Type_Group##### What I want to do is locate the starting position of Type, which is anywhere from 3 to 4 letters long (in this example it's either MSM or PWID), the starting position of Group which is 2-3 letters long (either HN or HMC), and finally the starting position of the 5-digit number. I'm able to get Type and Group using the following: TYPE_s <- sapply(c("MSM", "PWID"), regexpr, ID, ignore.case=T) GROUP_s <- (sapply(c("HN", "HMC"), regexpr, ID, ignore.case=T)) What I am having trouble with is getting the starting position of the 5-digit number. I am trying: DIGITS_s <- sapply("([0:9])", regexpr, ID, ignore.case=T) But that just seems to look for the position of the first 0.: > DIGITS_s ([0:9]) [1,] 13 [2,] 13 [3,] 13 [4,] 14 [5,] 14 [6,] 14 [7,] -1 [8,] -1 [9,] -1 [10,] -1 [11,] 17 [12,] 17 [13,] -1 [14,] -1 [15,] -1 [16,] -1 [17,] -1 [18,] -1 [19,] -1 [20,] -1 [21,] 17 [22,] 17 [23,] -1 [24,] -1 [25,] -1 [26,] -1 [27,] -1 [28,] -1 [29,] -1 [30,] -1 [31,] 17 [32,] 17 [33,] -1 [34,] -1 [35,] -1 [36,] -1 [37,] -1 [38,] -1 [39,] -1 [40,] -1 [41,] 17 [42,] 17 [43,] -1 [44,] -1 [45,] -1 [46,] -1 [47,] -1 [48,] -1 [49,] -1 [50,] -1 [51,] 17 [52,] 17 [53,] -1 [54,] -1 [55,] -1 [56,] -1 [57,] -1 [58,] -1 [59,] -1 [60,] -1 [61,] 17 [62,] 17 [63,] -1 [64,] -1 [65,] -1 [66,] -1 [67,] -1 [68,] -1 [69,] -1 [70,] -1 [71,] 17 [72,] 17 [73,] -1 [74,] -1 [75,] -1 [76,] -1 [77,] -1 [78,] -1 [79,] -1 [80,] -1 [81,] 18 [82,] 17 [83,] 17 [84,] 17 [85,] 17 [86,] 17 [87,] 17 [88,] 17 [89,] 17 [90,] 17 [91,] 17 [92,] 17 [93,] 17 [94,] 17 [95,] 17 [96,] 17 [97,] 17 [98,] 17 [99,] 17 [100,] 17 So, clearly, this is wrong. I just would like to find the starting position of the first digit, no matter what it is. It's probably easy, isn't it? Best, Jen [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.