How to only lowercase quoted string in VIM

Question

Say I have a file with the following content:

Apple 'BANANA' ORANGE 'PEACH'

What is the regex to convert all quoted uppercase to lowercase?

The expected output file should look like:

Apple 'banana' ORANGE 'peach'

Answer 1

Try

:%s/'\w\+'/\=tolower(submatch(0))/g

'\w\+' match any word that is inside quotes. and replace it with the lowercase version of the match. \= tells substitute to evaluate the expression tolower(submatch(0)) where tolower() switches the string found in submatch(0) (the whole match) to lower case.

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You can also use the \L atom to turn the string after it to lower case and \0 is the same as submatch(0)

:%s/'\w\+'/\L\0/g

Take a look at :h s/\L