CODEWITHSUNDEEP
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Carlos Danger
Carlos Danger

Reputation: 155

Subset row in dataframe by values

 STEST                           TEST  CRESULTC CRESULTS CUNIT SIRESULC SIRESULT SIUNIT VWEEK TYPE    WKSLAB SILO SIHI CNLO
1   TALT                     ALT (SGPT)               85.0  IU/L                85   IU/L    -1    1 -2.142857    0   55  0.0
2   TAST                     AST (SGOT)               74.0  IU/L                74   IU/L    -1    1 -2.142857    0   40  0.0
3   TALB                        Albumin                4.3  g/dL                43    g/L    -1    1 -2.142857   36   48  3.6
4   TALP           Alkaline Phosphatase               45.0  IU/L                45   IU/L    -1    1 -2.142857   25  160 25.0
5   AMMB               Ammonium Biurate None Seen      NaN       NoneSeen      NaN           -1    1 -2.142857  NaN  NaN  NaN
6 AMURPH Amorphous Urates or Phosphates None Seen      NaN       NoneSeen      NaN           -1    1 -2.142857  NaN  NaN  NaN

Let's say that I have this dataframe, and its named labs. I want to subset it by multiple row values. For example, I need to extract only the rows where the value TEST is equal to Albumin or Ammonium Biurate.

D1 = subset(labs, labs$TEST == 'Albumin' & labs$TEST == 'Ammonium Biurate')

Yet after running this code, I get a dataframe with 0 objects? How do I subset by multiple row conditions in R properly? 

D1 = subset(labs, labs$TEST == 'Ammonium Biurate' | labs$TEST == 'Albumin')

D1 = subset(labs, labs$TEST %in% c('Ammonium Biurate, Albumin)

Edit : Thanks for the suggestion with %in%. The use of == will search for patterns in the TEST column which follow the vector only.

Upvotes: 1

Views: 206

Answers (1)

pfifas
pfifas

Reputation: 592

As akrun alluded to above, your subset statement does not match the criterion you mention.

Instead of writing 

D1 = subset(labs, labs$TEST == 'Albumin' & labs$TEST == 'Ammonium Biurate')

write

D1 = subset(labs, labs$TEST == 'Albumin' | labs$TEST == 'Ammonium Biurate')

Your version is a logical AND, which is never true in your case, since the test value is never both at the same time. A logical OR is closer to what you where looking for, i.e. it's either Albumin or Ammonium Biurate, not both.

PS: Try to provide an easily reproducible example next time. It's simpler to immediately test an idea on your problem then.

Upvotes: 1

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