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How to select the last column of dataframe
(8 answers)
Closed 4 years ago.
Hello I have a data frame in python jupyter notebook and need to take the last column of it. How Can I take the last column of data frame?
Use iloc index, it should do the trick
df.iloc[:,-1]
It works on such way that : selects all rows and -1 selects last column
Related
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The difference between bracket [ ] and double bracket [[ ]] for accessing the elements of a list or dataframe
(11 answers)
Dynamically select data frame columns using $ and a character value
(10 answers)
Closed 10 days ago.
I'm new to R so this might be a dumb question but can someone help me out clarifying the $ function in R please? I know that $ is used to extract a specific "part" from the data frame. Is it correct that it is extracting one whole column of the data frame? not a specific element in the column nor one whole specific row? The $ sign only worked for me when the variables were as columns. Is this correct?
Tried manipulating the data frame to see different results.
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Dealing with spaces and "weird" characters in column names with dplyr::rename()
(1 answer)
R dplyr filter column with column name that starts with number
(1 answer)
Closed 2 years ago.
The filter in the first picture is clearly not working. None of the rows are filtered. However, in the second picture, there are clearly much less rows that satisfy the condition average value < good(blue) than the first picture.
Why is the code in the first picture not working and what may be a possible solution?
This question already has answers here:
Replace all particular values in a data frame
(8 answers)
How do I deal with special characters like \^$.?*|+()[{ in my regex?
(2 answers)
Closed 4 years ago.
I have a large data frame with a character value in various columns and rows. The character is [subnet].
I am trying to get rid of it by writing the following code
new_data[]=lapply(new_data, gsub, pattern="[subnet]", replacement='')
However, it seems like although "subnet" is disappearing, I am ending up with
"[]" for every instance of the character.
Any idea or fix would be appreciated.
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How to find all numeric columns in data
(2 answers)
Closed 4 years ago.
I have a list of 185 data-frames. I'm trying to edit them so each data frame only shows its numeric columns and also 2 specific, non-numeric ones.
I've had many issues with solving this, so I plan to use a for loop and find the column numbers of all numeric columns, use match to do the same for the two specific ones and then use c() to overwrite the data-frames.
I can pull the column number for the specific ones with
match("Device_Name",colnames(DFList$Dataframe))
successfully.
However, I cannot figure out how to return the numbers for all integer columns in a data-frame.
I have tried
match(is.numeric(colnames(DFList$Dataframe)),colnames(DFList$Dataframe))
and
match(class == "numeric",colnames(DFList$Dataframe),colnames(DFList$Dataframe))
to name a few, but now I am just taking wild stabs in the dark. Any advice would be welcome.
which(sapply(DFList$Dataframe,is.numeric))
This question already has answers here:
Dynamically select data frame columns using $ and a character value
(10 answers)
Closed 8 years ago.
I apologize since I'm sure this is an obvious issue, but I just can't seem to find the correct search terms to come up with the answer.
If I have a dataframe like this:
example<-cbind(rbind(1,2,3),rbind("a","b","c"))
colnames(example)<-c("a","b")
example<-as.data.frame(example)
And I want to extract the values from column a using a variable x,
x<-a
How do I go about this? When I try:
example$x
I get a null. How do I make this work?
I'm assuming a is a character:
x <- "a"
example[,x]