Lua: Replace characters in a string

Question

I have strings like

abcdef
abcd|(
abcde|(foo 
abcd|)
abcde|)foo

which should be modified to

abcdef
abcd
abcde \foo 
abcd
abcde \foo

if there is no | then do nothing
if nothing follows the |( or |) then delete these two characters
if something follows then replace |( or |) with <space>\

I am interested in short pattern expressions, if possible. I can do this by several string.find and string.sub but then I have a lot of if statements.

Do you mean the position at the end of the string with if nothing follows? — Wiktor Stribiżew
– Wiktor Stribiżew, Commented Oct 3, 2018 at 7:56
Yes, then |( or |) are the last characters. If there is no |, then bar) should be unchanged — Red-Cloud
– Red-Cloud, Commented Oct 3, 2018 at 8:01

Wiktor Stribiżew · Accepted Answer · 2018-10-03 08:01:52Z

1

You may use

function repl(v)
    res, _ = string.gsub(v:gsub('|[()]$', ''), '|[()]', ' \\')
    return res
end

See Lua demo online

Details

'|[()]$' matches | and then either ( or ) at the end of the string, and string.gsub replaces these occurrences with an empty string
|[()] then matches | and then either ( or ) anywhere in the string, and string.gsub replaces these occurrences with a space and \.

answered Oct 3, 2018 at 8:01

Wiktor Stribiżew

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8 Comments

Red-Cloud Over a year ago

Ups, I just realized that I forget something. A string like abcd|foo is also possible and should be changed to abcd \foo.

Wiktor Stribiżew Over a year ago

@Herbert Replace '|[()]' with '|[()]?'

H_H Over a year ago

@WiktorStribiżew how to replace the [[_TOC_]] in lua script? it has special characters.

Wiktor Stribiżew Over a year ago

@H_H Only [ is special, so %[%[_TOC_]]

H_H Over a year ago

@WiktorStribiżew I apply same rules for [^\%[2\%]^] string but, it doesn't work. I have tried with %[^\%%[2\%]^]. Am I missing something here? I am trying to replace in lua script. Thanks!

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