I am attempting to pull a table from SQLServer and convert it to a vector in R.
I use sqlQuery() to return the table, which looks to be returned as a dataframe. I am curious, can I change all the values in this dataframe to be a vector?
I am currently using as.vector(nameofdataframe), which converts it to a list. I find that if I use as.vector(dataframe$column), it returns a vector, but I have many columns and I feel like there should be a much more simple way.
I was able to figure it out. If you take the data frame resulting from a sqlQuery() you need to use as.matrix first and then as.vector to the resulting matrix. Thank you all for your help.
Related
Sorry if this is a duplicate, I read through a number of threads but couldn't really find a good explanation.
I have a dataset (dataframe) where I calculated the mean value of each column. I now want to do some logical comparisons between these values. I used lapply to get the means
means_list <- lapply(dataset_df, mean)
which outputs a named list. But when I try to compare two elements of this list, e.g.
means_list["condition1"] > means_list["condition2"]
I get an error ("comparison of these types is not implemented").
I don't get that error if I use sapply instead so that I'm working with a named vector. I can also get around the error by converting the list to a dataframe with as.data.frame first.
So, I feel like I'm doing something wrong when subsetting a named list here but I don't quite understand how. Is there a correct way to subset the list so that I can do the logical comparison? Or is this not possible with named lists?
Thanks!
To access to the element of a list by its name, you have to use double brackets:
means_list[["condition1"]] > means_list[["condition2"]]
I have two different data frames, each of them consisting of a list of "genes" and a list of "interactors" (other genes). Is it possible with R to check if there any "genes" from one list that are also present in any of the columns of "interactors" from the other data frame, and vice-versa?
I am quite new in R, so perhaps there is an easy way to perform this, but I don't even know how to look for it.
Thanks in advance!
Guillermo.
please can you show a sample of your data?
In any case, I guess the following is what you need:
df_common<-data.frame(df[which(df$genes %in% df$interactors),])
it is checking which elements in the column "genes" in the data frame df are also present %in% the column "interactors" in the same data frame
Is it this what you are looking for? if not, please paste input and desired output
I am a beginner in R program.
I imported a csv file. This file only contains one column with 50 characters, but R classifies it as a dataframe. I need all possible combinations within elements of this column. I think I need to work with a vector not with a data frame, how can I do it?
Thank you!
Actually your data frame already contains the vector you need. You can call it with
dataframe$column_name
The text before the $ operator specifies your data frame, and after is your vector, which is a column in your data frame. So when you run your calculations you can just write
function(dataframe$column_name)
In your specific case with a single vector, it may be simplest to change the dataframe into a 2d vector. But when you start manipulating your data, you'll likely store more vectors of variables. You'll want to keep those vectors organized within data frames.
Do you mean unlist?
You can use it to change a data frame into a vector, then you can use combn to get combination.
Is it possible to feed R a character string and for it to know I'm looking for the data frame with that name?
Example:
TestData <- matrix(1:100,nrow=10, ncol=10)
Then, if I want to reference it later, can I do something similar to this to have R pull dataset?
paste("TestData$",x[1,],sep="")
When entered this way, it comes up as a character string and obviously returns no data. For context, I'm trying to do it this way because I'm creating a loop that goes through several data sets (and columns within those datasets), but does similar operations, so I would like to be able to dynamically change the referenced dataset.
Any help is appreciated. Thanks!
Ok, I'm stuck in a dumbness loop. I've read thru the helpful ideas at How to sort a dataframe by column(s)? , but need one more hint. I'd like a function that takes a matrix with an arbitrary number of columns, and sorts by all columns in sequence. E.g., for a matrix foo with N columns,
does the equivalent of foo[order(foo[,1],foo[,2],...foo[,N]),] . I am happy to use a with or by construction, and if necessary define the colnames of my matrix, but I can't figure out how to automate the collection of arguments to order (or to with) .
Or, I should say, I could build the entire bloody string with paste and then call it, but I'm sure there's a more straightforward way.
The most elegant (for certain values of "elegant") way would be to turn it into a data frame, and use do.call:
foo[do.call(order, as.data.frame(foo)), ]
This works because a data frame is just a list of variables with some associated attributes, and can be passed to functions expecting a list.