Improve operator summary (#5880)

Signed-off-by: Ben Sherman <[email protected]>
Co-authored-by: Chris Hakkaart <[email protected]>

Author: bentsherman

docs/channel.md

@@ -80,33 +80,27 @@ See {ref}`channel-factory` for the full list of channel factories.
 
 ## Operators
 
-Operators are methods that consume and produce channels. Because channels are asynchronous, operators are necessary to manipulate the values in a channel, without using a process. As a result, operators are useful for implementing the "glue logic" between processes.
+Channel operators, or _operators_ for short, are functions that consume and produce channels. Because channels are asynchronous, operators are necessary to manipulate the values in a channel, aside from using a process. As a result, operators are useful for implementing the _glue logic_ between processes.
 
-See {ref}`operator-page` for the full list of operators. If you are new to Nextflow, here are some commonly-used operators to learn first:
+Commonly used operators include:
 
-Filtering:
+- {ref}`operator-combine`: emit the combinations of two channels
 
-- {ref}`operator-filter`: select all values in a channel that satisfy a condition
-- {ref}`operator-first`: select the first value in a channel
-- {ref}`operator-take`: select the first *n* values in a channel
-- {ref}`operator-unique`: select the unique values in a channel (i.e. remove duplicates)
+- {ref}`operator-collect`: collect the values from a channel into a list
 
-Transforming:
+- {ref}`operator-filter`: select the values in a channel that satisfy a condition
 
-- {ref}`operator-collect`: collect the values from a channel into a list
-- {ref}`operator-grouptuple`: group the values from a channel based on a grouping key
-- {ref}`operator-map`: transform each value from a channel with a mapping function
-- {ref}`operator-reduce`: accumulate each value from a channel into a single value
+- {ref}`operator-flatMap`: transform each value from a channel into a list and emit each list 
+element separately
 
-Combining multiple channels:
+- {ref}`operator-grouptuple`: group the values from a channel based on a grouping key
 
-- {ref}`operator-combine`: emit the combinations of two channels
-- {ref}`operator-concat`: emit the values from multiple channels (in the order in which the channels were given)
 - {ref}`operator-join`: join the values from two channels based on a matching key
-- {ref}`operator-mix`: emit the values from multiple channels (in the order in which items arrive)
 
-Miscellaneous:
+- {ref}`operator-map`: transform each value from a channel with a mapping function
+
+- {ref}`operator-mix`: emit the values from multiple channels
 
-- {ref}`operator-ifempty`: emit a channel, or a default value if the channel is empty
-- {ref}`operator-set`: assign a channel to a variable
 - {ref}`operator-view`: print each value in a channel to standard output
+
+See {ref}`operator-page` for the full list of operators.