For your sample data, the OPs specifications, should lead to an ordering of:

copy carpet soap error prawn emblem cabin echo pail engine reptile esk
+imo skunk

[download]

Not:

carpet error prawn reptile emblem engine echo eskimo copy soap cabin p
+ail skunk

[download]

Consider the OPs 3-part specification and the following:

orig    pre-r   sort-r          pre-e   sort-e          pre-o   sort-O
+          final

cabin                                                   cabin   copy  
+          copy
prawn   prawn   carpet                                                
+          carpet
pail                                                    pail    soap  
+          soap
error   error   error                                                 
+          error
reptile reptile prawn                                                 
+          prawn
engine                          engine  emblem                        
+          emblem
copy                                                    copy   cabin  
+          cabin
echo                            echo    echo                          
+          echo
soap                                                    soap   pail   
+          pail
eskimo                          eskimo  engine                        
+          engine
carpet  carpet  reptile                                               
+          reptile
emblem                          emblem  eskimo                        
+          eskimo
skunk                                                   skunk  skunk  
+          skunk

[download]

The problem with your algorithm is, that is doesn't exclude those items that match the first criteria, from being considered by the second criteria, if the also match it; but the OPs specifications (emphasis added):

all the strings inside the array that contain an “r” and sort those in ascending alphabetical order. For the elements that are left, find the ones that start with an “e” and sort those by ascii value of their third character. And for the ones that are left reverse sort by their last letter alphabetically.

Your algorithm does not exclude items that contain an 'r' from being considered when processing items that start with an 'e'. Eg. 'error'.

Nor does it exclude items that contain an 'r', or start with an 'e', from being processed when reverse sorting "the ones that are left".

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In reply to Re^2: How to perform different sorts on multiple sections of items in the same array by BrowserUk
in thread How to perform different sorts on multiple sections of items in the same array by estreb

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