How to flip array keys and values in the code editor?

Easy, with regex search!

• Press Ctrl+R for show replace bar
• Enable regex mode (button looks like .* near search field)
• Use regex in search field: '(.+)'\s=>\s'(.+)',
• Use expression for replace: '$2' => '$1',

You can see a tooltip with a value that will be after replace

It is possible even you have different quotes and spaces between arrow

Use regex
(?:'|")(.+)(?:'|")\s{0,}=>\s{0,}(?:'|")(.+)(?:'|"),

And the same replace expression '$2' => '$1',

Named capture groups also available:

Use regex
(?:'|")(?<src>.+)(?:'|")\s{0,}=>\s{0,}(?:'|")(?<tgt>.+)(?:'|"),

And the same replace expression '${tgt}' => '${src}',

Comments

[Sérgio Araújo]

As a test I have tried on vim

/\v^('\w+')( .. )('\d+'),
:%s//\3\2\1,

OBS: I have used the caret as if the pattern started at the begining of line but we can also cosider the space optional

/\v^(\s+)?('\w+')( .. )('\d+'),
:%s//\1\4\3\2

Another tip: Using neovim we have the "inccommand" that allow us to match our regex icrementally. Then we can refer to our search simply by using //

[rulatir]

"Easy" and "with regex search" are mutually exclusive concepts, and I am saying this as a regex enthusiast who routinely fixes other people's code by replacing naïve matching like strpos() with preg_match().