Use values in vector to add rows in dataframe

Question

I have a vector of names:

nums = 1:5
names = paste("name_", nums, sep="")

And a data frame where col1 contains a subset of the values listed in names:

Name    Count
name_1  14
name_3  2
name_5  11

I would like to use the vector of names to add rows to the data frame for names that are currently missing from the data frame, so that the final product looks like this:

Name    Count
name_1  14
name_2  0
name_3  2
name_4  0
name_5  11

I've come across some other variations of this question, but can't seem to find a solution that matches my scenario. Thanks for any help!

akrun · Accepted Answer · 2019-09-30 18:37:21Z

4

One option is complete

library(tidyr)
complete(df1, Name = names, fill = list(Count = 0))
# A tibble: 5 x 2
#  Name   Count
#  <chr>  <dbl>
#1 name_1    14
#2 name_2     0
#3 name_3     2
#4 name_4     0
#5 name_5    11

data

df1 <- structure(list(Name = c("name_1", "name_3", "name_5"), Count = c(14L, 
2L, 11L)), class = "data.frame", row.names = c(NA, -3L))

answered Sep 30, 2019 at 18:37

akrun

891k38 gold badges590 silver badges700 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

IceCreamToucan · Accepted Answer · 2019-09-30 18:47:44Z

3

You can merge and then replace the NAs resulting from non-matches with 0

out <- merge(df, data.frame(Name = names), all = TRUE)
out$Count <- with(out, replace(Count, is.na(Count), 0))

out
#     Name Count
# 1 name_1    14
# 2 name_2     0
# 3 name_3     2
# 4 name_4     0
# 5 name_5    11

answered Sep 30, 2019 at 18:47

IceCreamToucan

28.8k2 gold badges27 silver badges48 bronze badges

Comments

d.b · Accepted Answer · 2019-09-30 18:48:26Z

3

data.frame(names, Count = pmax(df1$Count[match(names, df1$Name)], 0, na.rm = TRUE))
#   names Count
#1 name_1    14
#2 name_2     0
#3 name_3     2
#4 name_4     0
#5 name_5    11

edited Sep 30, 2019 at 18:48

answered Sep 30, 2019 at 18:40

d.b

32.6k6 gold badges46 silver badges90 bronze badges

1 Comment

IceCreamToucan Over a year ago

Huh, so R does have a built-in coalesce function, it's just hidden in a max function. Never would have guessed

Collectives™ on Stack Overflow

Use values in vector to add rows in dataframe

3 Answers 3

data

Comments

Comments

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

data

Comments

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related