This came up a few months ago. Check the thread on hashing and partial matching around Nov 18. The short answer is no, you can't turn it off because lots of code relies on that behavior.
Reid Huntsinger -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of McGehee, Robert Sent: Thursday, January 27, 2005 9:34 AM To: [email protected] Subject: [R] Indexing Lists and Partial Matching I was unaware until recently that partial matching was used to index data frames and lists. This is now causing a great deal of problems in my code as I sometimes index a list without knowing what elements it contains, expecting a NULL if the column does not exist. However, if partial matching is used, sometimes R will return an object I do not want. My question, is there an easy way of getting around this? For example: > a <- NULL > a$abc <- 5 > a$a [1] 5 > a$a <- a$a > a $abc [1] 5 $a [1] 5 Certainly from a coding prospective, one might expect assigning a$a to itself wouldn't do anything since either 1) a$a doesn't exist, so nothing happens, or 2) a$a does exist and so it just assigns its value to itself. However, in the above case, it creates a new column entirely because I happen to have another column called a$abc. I do not want this behavior. The solution I came up with was to create another indexing function that uses the subset() (which doesn't partial match), then check for an error, and if there is an error substitute NULL (to mimic the "[" behavior). However, I don't really want to start using another indexing function altogether just to get around this behavior. Is there a better way? Can I turn off partial matching? Thanks, Robert Robert McGehee Geode Capital Management, LLC 53 State Street, 5th Floor | Boston, MA | 02109 Tel: 617/392-8396 Fax:617/476-6389 mailto:[EMAIL PROTECTED] This e-mail, and any attachments hereto, are intended for us...{{dropped}} ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
