Count difference in row data between two data frames in R


Count difference in row data between two data frames in R



I have two data frames (a1 and a2).



The first (a1) is an original dataset and the second (a2) is the same, only contains data that has been appended to some records. I want to get a count of the number of records that contain appended data. I don't need to view the records.



What is the best way to just get a count of the number of records that are different in a2?





Its not clear what you're asking, A simple example would help. See stackoverflow.com/questions/5963269/…
– Ryan
Jun 29 at 16:08





Please, provide a Minimal, Complete, and Verifiable example. From your description it is not clear what the difference between dataframes a1 and a2 is, especially what you mean by contains data that has been appended to some records. Thank you.
– Uwe
Jun 29 at 16:35


a1


a2




2 Answers
2



Ok, so first let me get this straight. You basically want to compare two dataframes and find the number of different columns.



Using dplyr


> a1
a b
1 1 a
2 2 b
3 3 c
4 4 d
5 5 e

> a2
a b
1 1 a
2 2 b
3 3 c

> df <- setdiff(a1,a2)
a b
1 4 d
2 5 e

> nrow(df)
2



Is this what you are looking for?



Using anti_join from dplyr: anti_join a2 with a1 will result in the records that are in a2, but not in a1. and tally will count the rows.


a2 %>%
anti_join(a1) %>%
tally()






By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.

Comments

Post a Comment

Popular posts from this blog

paramiko-expect timeout is happening after executing the command

paramiko-expect timeout is happening after executing the command Can someone help me why timeout is happening after executing the command .I am trying to SSH to a machine and execute a command.I want to store the result of the executed command . I have referred paramiko-timeout but i didn't get my expected result. import traceback try: import paramiko except ImportError: raise Exception("Please install paramiko , pip install paramiko") import pexpect from paramiko_expect import SSHClientInteraction def main(): HOSTNAME = "minion5.net" USERNAME = "root" PASSWORD = "help@432" PROMPT = "root@*:~$s+" try: client = paramiko.SSHClient() client.load_system_host_keys() client.set_missing_host_key_policy(paramiko.AutoAddPolicy()) client.connect(hostname=HOSTNAME, username=USERNAME, password=PASSWORD) with SSHClientInteraction(client, timeout=20, display=True) as interact: ...
Read more

Opening a url is failing in Swift

Opening a url is failing in Swift breakpointing inside the callback and logging success shows false. I added itms-apps to my plist: LSApplicationQueriesSchemes and put this in my app delegate: func application(_ app: UIApplication, open url: URL, options: [UIApplicationOpenURLOptionsKey : Any] = [:]) -> Bool { return true } func moreTapped() { let url = NSURL(string: "itms-apps://itunes.com/developer/quantum-productions/id979315877") if #available(iOS 10.0, *) { UIApplication.shared.open(url! as URL, options: [:], completionHandler: {(success: Bool) in }) } else { UIApplication.shared.openURL(url! as URL) } } Are you testing on a real device? – rmaddy Jun 21 at 23:57 I try on a device, get "Cannot Connect to App Store". Device is online ...
Read more

Export result set on Dbeaver to CSV

Export result set on Dbeaver to CSV Normally I use Dbeaver for windows and always export my result set like this: run my query --> select the result --> export the result set --> select export to clipboard --> done This step by step puts my result set in my clipboard and I can paste it wherever I want to work with it. The problem is that now I am using dbeaver for mac and this guide is not working. I can go on until the moment that I select my result set like in the image below: exporting data set But once I go further in the process, in the last step I get: no query Note that in "source" it was suppose to show the query that originated the result set, but instead it says just "select. As a result it does't select my result or anything (besides being "successful"). Normally my query would show up there automatically and I couldn't find any option that corrects this problem in the menus. Please help me! Thanks. Aft...
Read more