Xcode, getting unused Variable message - xcode4

Am new to programming. Got a little problem with Xcode. I get this message "UNUSED VARIABLE"
for a small basic variable input.
int x;

The message is telling you what it's telling you. You've declared a variable but aren't using it. It's not an error, just a warning.

Related

What does this error message mean (creating an input-file for MODifieR) and how to fix it?

I am trying to create an input-file that can be used for different types of module-identification packages in the "MODifieR"-program, but I get this error message: "The condition has a length>1".
I am still pretty new to R and have just started using these programs so I have no idea what the message means or how to fix it... Greatful for any help!
I haven't tried anything yet, apart from restarting R and reloading all packages/code, as I have little idea of what I am doing :)

Getting an error when intry to load a dataframe

Getting a syntax error and not sure why. Trying to loadca dataframe. Please can someone help. Thanks
If you are getting started with programming, jupyter can be counter intuitive at some points, I assume that's not your first cell in the notebook, so be sure to run the previous ones where the definition for titanic_df/titanic_csv is loaded.
The error you are getting says NameError, not SyntaxError, and it is informing you that a variable called titanic_csv does not exist.

How to print in r source stops

have a code that calls different codes inside it with source function. if an error occurs when running a source i would like to save the information of the error that appears but im not being able to do it. Does anyone know if this is possible? Thanks!
Did you try traceback() after the error occurred? You can also set it in options(error = traceback). I think RStudio IDE provides tracebacks by default.

R Error: names() applied to a non-vector

I have a chunk of code which produces an error only the first time I run it. Strangely if I run it a second time I get no error (craziness definition?). Also the error does not show up always at the same position, I mean that if I add a few lines of comments the error message is printed after the comments and not after a specific instruction.
I cannot provide a reproducible example because I do not know where exactly the error comes from. The error is the following:
Error in names(frame)[names(frame) == "x"] <- name :
names() applied to a non-vector
I should specify that in my code I don't have -at least explicitly- a names() function.
This is a tricky error. I was able to track down the reason and it seems to be that R has an object of the same name as the function cached. This is most likely if using an IDE such as RStudio a tab for View(df). Unless the tab is closed even running the function without code will give you this error. Likewise, if the tab is not closed not even removing all objects or doing a garbage collection will solve it. Once the tab is closed the error will be gone.
I had the same error, and It was faulting on a particular function that I wrote. It was throwing the error whenever I loaded the function, even when the I commented out all the code in the function. I found that changing the variable name of my function stopped the error. My only guess is that there is some weird variable name conflict.
I had the same error. The reason for it is something related to a file I saved long ago with the name "df", which is interfering with a current variable, also called df.
The solution however is straigthforward: Find the problematic line, by running the first line of the code, then clearing the global environment, and running it again. If no error occurs, add the next line, and so forth until the error occurs. Then, change the name of the variable in that line.
Even I had the same error. The reason in my case was that there was another data frame with the same name as the function inside the function. I guess R throws this error when there is a type mismatch as well. In my case the name was first read as a function. When R came across the same name again, it would be looking for a function but instead found a data frame.
All I had to do was change the name of one of them and the error was gone.
This error also appears in my code everytime when I tried to delete everything through remove(list = ls()). In my case the problem was, that I had an object named df (datatype = data.frame) and also had the View opened of a previous version of df. After closing the View the error disappeared.
Just add
as.vector(dataframe)
This works.

Getting an error in using particular "?" this operator,How to use it in swirl?

I am using swirl package for R programming. And for that, in a particular part I have to give this command which gives this error and that's why can't progress further.
?c
Error in shell.exec(url) :
file association for 'https://127.0.0.1:19202/library/base/html/c.html' is not available or invalid
Please help me to solve this problem, otherwise I am stuck here and can't get any progress.
Type below,It worked for me
info()
skip()

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