Existing function that will detect equal values across a data row

[jtbrown1980]

I'm trying to find a way to remove rows with equal values in all columns for various data frames.
The data frames will never be larger than 500 rows by 10 columns so size is not an issue.

Before and after are below. rows 2 and 5 were dropped in df_after because each row contained a value that was equal in all columns.

Thank you for your assistance on this. I'm still very new to R so any guidance is always welcomed.

df_before <- data.frame("x1" = c("a","b","c","d","e"), "x2" = c("c","b","c","x","e"), "x3" = c("a","b","t","s","e"))

df_after<- data.frame("x1" = c("a","c","d"), "x2" = c("c","c","x"), "x3" = c("a","t","s"))

[joels]

Here's a base R solution:

df_after = df_before[apply(df_before, 1, function(x) length(unique(x)) > 1), ]

I don't do row-wise operations often enough to remember what the current tidyverse idiom is, but another option is to convert to long format for the filtering and then convert back to wide. The code below seems awfully long to me, so maybe there's a less verbose approach.

df_after = df_before %>% 
  rownames_to_column() %>% 
  gather(key, value, -rowname) %>% 
  group_by(rowname) %>% 
  filter(length(unique(value)) > 1) %>% 
  spread(key, value) %>% 
  ungroup %>% 
  select(-rowname)

A shorter hybrid solution:

df_before %>% 
  filter(apply(., 1, function(x) length(unique(x)) > 1))

[jtbrown1980]

Thank you! This helps so much.