Concat_ws() function in Sparklyr is missing

Question

I am following a tutorial on web (Adobe) analytics, where I want to build a Markov Chain Model. ( http:\/\/datafeedtoolbox.com\/attribution-theory-the-two-best-models-for-algorithmic-marketing-attribution-implemented-in-apache-spark-and-r\/<\/a> ).

But it looks like the function does not exists (after installing the package, and calling the library, I receive an error that the function does not exists...).

I tried:

• <\/li><\/ul>

  What is the goal of the function?<\/strong> Concatenates multiple input string columns together into a single string column, using the given separator.<\/em>

  "

Answer 1

You can simply use paste from base R.

library(sparklyr)
library(dplyr)

config <- spark_config()
sc <- spark_connect(master = "local", config = config)

df <- as.data.frame(cbind(c("1", "2", "3"), c("a", "b", "c")))
sdf <- sdf_copy_to(sc, df, overwrite = T)

sdf %>%
  mutate(concat = paste(V1, V2, sep = "-"))

Answer 2

You cannot find the function because it doesn't exist in sparklyr package. concat_ws is a Spark SQL function ( org.apache.spark.sql.functions.concat_ws ).

sparklyr depends on a SQL translation layer - function calls are translated into SQL expressions with dbplyr :

> dbplyr::translate_sql(concat_ws("-", foo, bar))
<SQL> CONCAT_WS('-', "foo", "bar")

This means that the function can be applied only in the sparklyr context:

sc <- spark_connect(master = "local[*]")
df <- copy_to(sc, tibble(x="foo", y="bar"))

df %>% mutate(xy = concat_ws("-", x, y))
# # Source: spark<?> [?? x 3]
#   x     y     xy     
# * <chr> <chr> <chr>  
# 1 foo   bar   foo-bar

Answer 3

I had a similar problem with dbplyr (BigQuery database).

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I kept getting the error:

<\/h3>
I wrote custom SQL and placed it inside sql()<\/code> .
<\/h3>
Once you know the SQL that will generate what you're after (in my case it was CONCAT(date_char, ' ', time_char)<\/code> ), then simply place it inside the sql()<\/code> function, like so: