How to count the number of observations in R like Stata command count

Question

aaa lt - data frame sex c 1 1 2 2 1 1   group1 c 1 2 1 2 2 2  group2 c  A   B   A   B   A   B      stata command   count if sex  1  amp  group1  2 count if sex  1  amp  group2   A    count counts the number of observations that satisfy the specified conditions  If no conditions are specified  count displays the number of observations in the data   How to count in R  Thank you

User · Answer

You can also use the filter function from the dplyr package which returns rows with matching conditions    gt  library dplyr    gt  nrow filter aaa  sex    1  amp  group1    2    1  3  gt  nrow filter aaa  sex    1  amp  group2     A     1  2

User · Answer

The with function will let you use shorthand column references and sum will count TRUE results from the expression s    sum with aaa  sex  1  amp  group1  2       1  3  sum with aaa  sex  1  amp  group2   A        1  2   As  mnel pointed out  you can also do   nrow aaa aaa sex  1  amp  aaa group1  2        1  3  nrow aaa aaa sex  1  amp  aaa group2   A         1  2   The benefit of that is that you can do   nrow aaa      1  6   And  the behaviour matches Stata s count almost exactly  syntax notwithstanding

[r] How to count the number of observations in R like Stata command count

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