How to calculate levels occurrence of factor column?

Question

df <- data.frame(
    cola = c('1','b','c','1','1','e','1',NA,'c','d'),
    colb = c("A",NA,"C","D",'a','b','c','d','c','d'),
    colc = c('a','b','c','d','a','b','c','d','c','d'),stringsAsFactors = TRUE)

df$cola is 1 b c 1 1 e 1 <NA> c d
I want to know how many 1 in this column(answer is 4),how to do it?

`length(which(df$cola == 1))` – Ronak Shah Apr 05 '19 at 04:24 — Ronak Shah, Apr 05 '19 at 04:24

score 2 · Accepted Answer · answered Apr 05 '19 at 04:12

2

You may use sum here:

num_ones <- sum(df$cola == "1", na.rm=TRUE)
num_ones

[1] 4

The na.rm=TRUE option is needed, because without it, the entire sum operation would "NA out", and just return NA. In this case, we can just ignore NA values.

answered Apr 05 '19 at 04:12

Tim Biegeleisen

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`sum(df$cola %in% "1")` would also work here. – jay.sf Apr 05 '19 at 06:25
3

@jay.sf It might also depend on the brand of `cola`. I prefer Coke over Pepsi, for obvious reasons :P – Tim Biegeleisen Apr 05 '19 at 06:26
1

You should really try VIVI Cola, it's a Swiss cola brewed with water from the Alps :) – jay.sf Apr 05 '19 at 07:40

How to calculate levels occurrence of factor column?

1 Answers1