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I have a column with a range 1:5. Many vectors contain the value twice, for example (33) instead of (3) and (11) instead of 1. Is there any code to delete these duplicates and keep one number within a vector?
Thanks a lot
Say your column is named y:
substr(y,1,1)
Takes from the first digit to the first digit (i.e. only the first) of y (element-wise). But substr outputs a character, to transform it back to numeric:
as.numeric(substr(y,1,1))
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How would I show (display) all rows of a data set whose average of columns 1 and columns 2 is great than 60
Assuming that you mean the average by row, and that the data frame is named yourdata, something like this should work:
yourdata[rowMeans(yourdata[1:2]) > 60, ]
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I'm interested to pull out instances where initials are used in my text data, as they are almost always two capital letters, is there a simple way to look for this text pattern using Grep in R?
If we need to match two upper case letters from the start (^) of the string, use grepl on the column concerned to return a logical expression within subset to subset the rows
subset(df1, grepl("^[A-Z]{2}", col1))
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Without using a special function, can you do the following to change the values in an R dataframe from a column that have length greater than 4:
df[length(df$Column1)>4,"Column1"] = "replacement value"
This does not seem to work, is there an alternative index style I can use, or do I need to use a function?
Thanks
The function to determine the length of an entry, like a word in a dataframe, is nchar(), and not length(). The latter is typically used to determine the number of entries in a vector.
You could therefore try using:
df[nchar(df$Column1) > 4, "Column1"] <- "replacement value"
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Number of digits that are present in the maximum number that is formed using three digits?
Maximum factorial that is formed by three digits?
This was a question asked on a site.
I am not able to understand is there any thing tricky i am not getting?
i have tried 3 and 720 but it is incorrect
The maximum factorial which can be formed using 3 digits is 999!.
The answer can be easily obtained from wolfram alpha.
Number of digits in 999!.
999!=Answer
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I loaded a RDS file. The file contains a numeric field. When I say
class(NEI$Emissions)
it returns
"numeric"
The data is in maximum 3 digits and contains 3 digits of decimal. However, when I issue the command
max(NEI$Emissions)
it returns a huge number.
646952
How can I use the numeric values as it is?
R doesn't lie. One of your data points is not what you expect.
Find which row has the problem with this command:
which.max(NEI$Emissions)
then examine that row of your original data. You will find the errant value.