How to replace a particular character after '=' sign in all the rows in notepad++

Question

My file content is as below

abcd-12=jksjd-jkkj
xyzm-87=hjahf-tyewg-iuoiurew
zaqw-99=poiuy-12hd-jh-12-kjhk-4rt45

I want to replace the hypen with underscore sign after the '=' i.e on the R.H.S of the equation.

No of hypenated terms are variable in the lines, it can be 3 or 4 or 5

How to do this for the entire document. Left hand side should be intact.

My desired result is :

abcd-12=jksjd_jkkj
xyzm-87=hjahf_tyewg_iuoiurew
zaqw-99=poiuy_12hd_jh_12_kjhk_4rt45

Answer 1

This will replace any number of hyphens in a single pass:

• Ctrl+H
• Find what: (?:=|(?!^)\G).*?\K-
• Replace with: _
• CHECK Wrap around
• CHECK Regular expression
• UNCHECK . matches newline
• Replace all

Explanation:

(?:             # non capture group
    =           # equal sign
  |             # OR
    (?!^)       # negative lookahead, make sure we are not at the beginning of a line
    \G          # restart from last match position
)               # end group
.*?             # 0 or more any character but newline, not greedy
\K              # forget all we have seen until this position
-               # a hyphen

Screen capture (before):

Screen capture (after):