Change value of a column based on whether string is in another column using R

Question

I want to create a new column based on whether a string is present in a different column of the dataframe.

 name
  Jon
  Anne
Jobraith
  Knut

Becomes:

 name      dummy
  Jon        1
  Anne       0
Jobraith     1
  Knut       0

looking for something along the lines of:

df$dummy <- ifelse('jo' in df$name, 1, 0)

hwnd · Accepted Answer · 2014-10-25 02:54:50Z

3

You could use grepl( ... ) to check for the substring ...

df <- data.frame(name = c('Jon', 'Anne', 'Jobraith', 'Knut'))
df$dummy <- as.numeric(grepl('jo', df$name, ignore.case=T))
df

#       name dummy
# 1      Jon     1
# 2     Anne     0
# 3 Jobraith     1
# 4     Knut     0

edited Oct 25, 2014 at 2:54

answered Oct 25, 2014 at 0:46

hwnd

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2 Comments

A5C1D2H2I1M1N2O1R2T1 Over a year ago

Why would you use ifelse here? Why not just as.numeric?

Luke Over a year ago

ifelse is nice though because it's a bit more general in the case that 0,1 isn't wanted

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