I have a file with hundreds of thousands of lines that start with a date, e.g.
2021-02-22...
but some odd lines do not start that way. My intention is to write a macro to find them and join them with the line above.
How can I search for such lines from within vim?
E.g., if I wanted to find the next matching line in vim, I would type
/^2021
and it would take me to the next line that starts with "2021"
I want to do this, but search for the next non-matching line.
My intention is to write a macro to find them and join them with the line above.
That kind of operation is usually done with :help :global:
:g!/<pattern>/<command>
which executes <command> on each line not matching <pattern>.
In your case, it would look like this:
:g!/^2021/-j
where…
^2021 is your pattern,-j first sets the address to the line above and then joins it with the following one.You may find this alternative more intuitive:
:g!/^2021/norm! kJ
which essentially uses the normal mode equivalent of :-j.
If you have several years in that file, consider a simple alternation:
:g!/^\(2021\|2020\|2019\)/-j
or a more generic pattern:
:g!/^\d\d\d\d-\d\d-\d\d/-j
You don't have to try to be smart, here, with quantifiers and negative look-behinds and stuff.
Reference:
:help :global
:help :range
:help :join
:help :normal
:help k
:help J
:help /^
:help \d
:help /\|
:help /\(
We can use look around regex in Vim to tackle this kind of question. If I understand you correctly, you want to search a line not starting with 2021, right?
The following search pattern works:
/\v^(2021)@!
A teardown of this search:
\v: use magic search, which will simplify the vim regex, see also :h \v.^: matches start of a line(2021)@!: @! is negative look ahead, i.e., after start of line, the following patter shouldn't be 2021, the parentheses here means a regex group.This finds and selects a non-empty line that does not start with 2021:
/^[^2]\([^0]\([^2]\([^1]\)\?\)\?\)\?.*
Explanation:
[^2] - expect a char that is not 2\([^<d>]\)\?, where <d> represents a digit