RegEx to swap only the first 2 digits of a middle part of a string? -

i seem have quite difficult task ahead need solve xquery , regular expressions.

the case: have alphanumeric string variable length of 20 30 chars first 2 digits of middle part (char 5 char(length-5)) of string should swapped , if there no or 1 digit in middle part 10th , 11th char of string should swapped.

so, few examples:

string: abcde12345fghij67890            (more 1 digit) output: abcde21345fghij67890            (swap first 2)  string: 1a2b3c4d5e6f7g8h9i0j1k2l3m4     (more 1 non adjacent digits) output: 1a2b3c5d4e6f7g8h9i0j1k2l3m4     (swap first 2 of middle part)  string: 34gf7asjkabaa4sfdlencxnkil9qrx  (only 1 digit in middle part) output: 34gf7asjkbaaa4sfdlencxnkil9qrx  (so, swap char 10 , 11) 

my pseudocode this:

function changestring(orgstring)    newstring:=replace(orgstring, regex-1st-digits-in-middle-pattern, regex-swap)   if newstring=orgstring #when there no 2 digits swap     newstring:=replace(orgstring, regex-10/11char, regex-swap)   return newstring 

i reckon there's no way whole solution in 1 line, that's why came above pseudocode. should correct find , replace regular expressions?

thanx in advance!

edit: forgot 1 thing in pseudocode... prevent swap of 10/11th char when first 2 digits of middle-string same number...

my pseudocode of course this:

string: whatever4any4any567whatever output: whatever4nay4any567whatever 

so need change compare this:

if count(digits in middlestring) < 2 

in pseudocode:

function changestring(orgstring)    newstring:=replace(orgstring, "^(.{5})(\d*)(\d)(\d*)(\d)(.*)(.{5})$", "$1$2$5$4$3$6$7")   if newstring=orgstring #when there no 2 digits swap     newstring:=replace(orgstring, "^(.{9})(.)(.)(.*)$", "$1$3$2$4")   return newstring 

explanation of first regex:

^      # anchor match start of string (.{5}) # match 5 characters, save them in backreference $1 (\d*)  # match number of non-digits, save in $2 (\d)   # match 1 digit, save in $3 (\d*)  # match number of non-digits, save in $4 (\d)   # match 1 digit, save in $5 (.*)   # match number of characters, save in $6 (.{5}) # match 5 characters, save in $7 $      # anchor match end of string 

test first regex on regex101.com.

test second regex on regex101.com.