r get number of rows

R: The Number of Rows/Columns of an Array

The Number of Rows/Columns of an Array. Description. nrow and ncol return the number of rows or columns present in x . NCOL and NROW do the same treating a vector as 1column matrix.

How do I get the number of rows of a data.frame in R? – Cross …

dataset will be a data frame. As I don’t have forR.csv , I’ll make up a small data frame for illustration: set.seed(1) dataset < data.frame(A = sample(c(NA, 1:100), 1000, rep = TRUE), B = rnorm(1000)) > head(dataset) A B 1 26 0.07730312 2 37 0.29686864 3 57 1.18324224 4 91 0.01129269 5 20 …

R: Number of rows for a DataFrame

nrow {SparkR}, R Documentation. Number of rows for a DataFrame. Description. Returns number of rows in a DataFrames. Usage. ## S4 method for signature ‘ DataFrame’ nrow(x). [Package SparkR version 1.5.1 Index]

R – Count number of rows matching a criteria – Stack Overflow

sum is used to add elements; nrow is used to count the number of rows in a rectangular array (typically a matrix or data.frame); length is used to count the number of elements in a vector. You need to apply … subset(mydata, sCode=’CA’, select=c(sCode)) , you should use sCode==’CA’ instead sCode=’CA’ .

R – Is it possible to get the number of rows in a CSV file without …

Not sure of its efficiency, but here’s a base R approach. Through a file connection , count.fields() counts the number of fields per line of the file. So if we take the length of the result, theoretically we should end up with the number of lines (rows ) in the file. length(count.fields(filename)). And if you have a …

Dataframe – count number of rows in a data frame in R based on group

Here’s the calculation of the number of rows per group, in two output display formats: … here’s an example using aggregate() , which is part of core R. aggregate() just needs something to count as function of the different values of MONTHYEAR . In this …. Suppose we have a df_data data frame as below

R – How to select no of rows from Data frame – Stack Overflow

… is by giving the index. Say, from the diamonds data set given with the ggplot2 package, I intend to select the first 1000 rows: library(ggplot2) data=diamonds subset_1=data[1:1000,]. For selecting some specific rows, use their row numbers. specific=c(1:100,104,105,110,400:900) subset_2=data[specific,] …

List – How to count rows? – Stack Overflow

Try this: myvec < sapply(mylist, NROW). length gives odd results with data. frames because data.frames are really lists of vectors of the same length. length( data.frame) is giving you the length of the underlying list, which is the number of columns of the data.frame. NROW and NCOL are nice because they ...

R – How to get number of rows for a specific value in a column – Stack …

I think the two methods offered so far are overly complex. Try either of these, the second of which is obviously the Right way. 🙂 (Borrowing @gung’s example.) # 1 > tapply( DF$MAJOR, DF$MAJOR, length) BIO ECON HIST LIT MATH 181 155 297 303 64 # 2 > table(DF$MAJOR) BIO ECON HIST LIT …

R – Return row number(s) for a particular value in a column in a …

I have a data frame (df) and I was wondering how to return the row number(s) for a particular value (2585) in the 4th column (height_chad1) of the same data frame? I’ve tried: row(mydata_2$height_chad1, 2585). and I get the following error: Error in factor(.Internal(row(dim(x))), labels = labs) : a matrixlike …

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