When I try to run the following function on Sybase ASE 15.7, it just spins indefinitely. Each component of the function seems to act as expected independently. This is simply a mechanism to strip all non-numeric characters from a string. Any and all thoughts appreciated.
create function dbo.mdsudf_just_digits(#str varchar(64))
returns varchar(64)
as
begin
while patindex('%[^0-9]%', #str) > 0
set #str = stuff(#str, patindex('%[^0-9]%', #str), 1, '')
return #str
end
-- A typical invocation would be like so:
select dbo.mdsudf_just_digits('hello123there456')
```
In Sybase (ASE) the empty string ('') actually translates into a single space:
select '.'+''+'.' -- period + empty string + period
go
---
. . -- we get a space between the periods
So in the current stuff(#str, ..., 1, '') you're actually replacing the first non-numeric with a single space. This 'new' space then matches the non-number test on the next pass through the loop at which point the space is replaced with ... another space. This is leading to an infinite loop of constantly replacing the first non-number character with a space.
You can get around this by using NULL as the last arg to the stuff() call, eg:
set #str = stuff(#str, patindex('%[^0-9]%', #str), 1, NULL)
Related
I need to check if the last character in a string is a digit, and if so, increment it.
I have a directory structure of /u01/app/oracle/... and that's where it goes off the rails. Sometimes it ends with the version number, sometimes it ends with dbhome_1 (or 2, or 3), and sometimes, I have to assume, it will take some other form. If it ends with dbhome_X, I need to parse that and bump that final digit, if it is a digit.
I use split to split the directory structure on '/', and use include? to check if the final element is something like "dbhome". As long as my directory structure ends with dbhome_X it seems to work. As I was testing, though, I tried a path that ended with dbhome, and found that my check for the last character being a digit didn't work.
db_home = '/u01/app/oracle/product/11.2.0/dbhome'
if db_home.split('/')[-1].include?('dbhome')
homedir=db_home.split('/')[-1]
if homedir[-1].to_i.is_a? Numeric
homedir=homedir[0...-1]+(homedir[-1].to_i+1).to_s
new_path="/"+db_home.split('/')[1...-1].join("/")+"/"+homedir.to_s
end
else
new_path=db_home+"/dbhome_1"
end
puts new_path
I did not expect the output to be /u01/app/oracle/11.2.0/product/dbhom1 - it seems to have fallen into the if block that added 1 to the final character.
If I set the initial path to /u01/app/.../dbhome_1, I get the expected /u01/app/.../dbhome_2 as the output.
You could use a regular expression to make matching a tad bit easier
if !!(db_home[/.*dbhome.*\z]) ..
You could use regex's
/[0-9]$/.match("How3").nil?
I need to check if the last character in a string is a digit, and if
so, increment it.
This is one option:
s = 'string9'
s[-1].then { |last| last.to_i.to_s == last ? [s[0..-2], last.to_i+1].join : s }
#=> "string10"
'/u01/app/11.2.0/dbhome'.sub(/\d\z/) { |s| s.succ }
#=> "/u01/app/11.2.0/dbhome"
'/u01/app/11.2.0/dbhome9'.sub(/\d\z/) { |s| s.succ }
#=> "/u01/app/11.2.0/dbhome10"
This is a starting point if you're running Ruby v2.6+:
fname = 'filename1'
fname[/\d+$/].then { |digits|
fname[/\d+$/] = digits.to_i.next.to_s if digits
}
fname # => "filename2"
And it's safe if the filename doesn't end with a digit:
fname = 'filename'
fname[/\d+$/].then { |digits|
fname[/\d+$/] = digits.to_i.next.to_s if digits
}
fname # => "filename"
I'm not sure if I like doing it that way better than the more traditional way which works with much older Rubies:
digits = fname[/\d+$/]
fname[/\d+$/] = digits.to_i.next.to_s if digits
except for the fact that digits gets stuck into the variable space after only being used once. There's probably worse things that happen in my code though.
This is taking advantage of String's [] and []= methods.
function exists(f)
filetry=""
local fileBuffer={}
for w in x:gmatch("%S+") do
table.insert(fileBuffer,w)
end
for i, v in ipairs(fileBuffer) do
filetry=filetry.."_"..v
end
f=filetry
if os.execute("test -e "..f) == true then
return true
else
return false
end
end
i need to change space characters to underscore
so i can find the file in termanal
i have tried to use apis but it's not working for me due to my computer deletes it after install it. so i just need a function that can make spaces , underscore and ,use the termanal test command to find a file
str = str:gsub("%s+", "_")
-- where `str` is the string you want to remove the spaces from.
-- Replaces multiple consecutive space characters with single _.
-- Remove the `+` to make it replace each space character with its own _.
Example:
print( ("Hello world"):gsub("%s+", "_") )
-- will print "Hello_world"
EDIT: Note that string.gsub() creates a new string instead of modifying the old one, which is why in my first example the reasignation str = str:gsub... was necessary.
I have a pl sql string as follows :
String := 'ctx_ddl.add_stopword(''"SHARK_IDX19_SPL"'',''can'');
create index "SCOTT"."SHARK_IDX2"
on "SCOTT"."SHARK2"
("DOC")
indextype is ctxsys.context
parameters(''
datastore "SHARK_IDX2_DST"
filter "SHARK_IDX2_FIL"
section group "SHARK_IDX2_SGP"
lexer "SHARK_IDX2_LEX"
wordlist "SHARK_IDX2_WDL"
stoplist "SHARK_IDX2_SPL"
storage "SHARK_IDX2_STO"
sync (every "SYSDATE+(1/1)" memory 67108864)
'')
/
';
I have to get search the final occurrence of '/' and add ';' to it. Also I need to escape the quotes preset in parameters ('') to have extra quotes. I need output like
String := 'ctx_ddl.add_stopword(''"SHARK_IDX19_SPL"'',''can'');
create index "SCOTT"."SHARK_IDX2"
on "SCOTT"."SHARK2"
("DOC")
indextype is ctxsys.context
parameters(''''
datastore "SHARK_IDX2_DST"
filter "SHARK_IDX2_FIL"
section group "SHARK_IDX2_SGP"
lexer "SHARK_IDX2_LEX"
wordlist "SHARK_IDX2_WDL"
stoplist "SHARK_IDX2_SPL"
storage "SHARK_IDX2_STO"
sync (every "SYSDATE+(1/1)" memory 67108864)
'''')
/;
';
Any help.
There's an age-old saying: "Some people, when confronted with a problem, think "I know, I'll use regular expressions." Now they have two problems"
Unless you are confronted by a problem that truly requires regular expressions, I'd recommend working with basic string manipulation functions.
Semi-colon:
Use INSTR to find last occurence of '/', call this P1.
Result = Substr from position 1 through P1||';'||substr from P1+1 through to end-of-string
Parameters substitution:
Use INSTR to find where parameter list starts (i.e. find "parameters(" in your string) and ends (presumably the last closing parenthesis ")" in your string). Call these P2 and P3.
Result = substr from 1 through P2 || REPLACE(substr from P2+1 through P3-1,'''','''''''') || substr from P3 to end-of-string
In Oracle I want to check whether the string has "=' sign at the end. could you please let me know how to check it. If it has '=' sign at the end of string, I need to trailing that '=' sign.
for eg,
varStr VARCHAR2(20);
varStr = 'abcdef='; --needs to trailing '=' sign
I don't think you need "pattern matching" here. Just check if the last character is the =
where substr(varstr, -1, 1) = '='
substr when called with a negative position will work from the end of the string, so substr(varstr,-1,1) extracts the last character of the given string.
Use the REGEX_EXP function. I'm putting a sql command since you didn't specify on your question.:
select *
from someTable
where regexp_like( someField, '=$' );
The pattern $ means that the precedent character should be at the end of the string.
see it here on sql fiddle: http://sqlfiddle.com/#!4/d8afd/3
It seems that substr is the way to go, at lease with my sample data of about 400K address lines this returns 1043 entries that end in 'r' in an average of 0.2 seconds.
select count(*) from addrline where substr(text, -1, 1) = 'r';
On the other hand, the following returns the same results but takes 1.1 seconds.
select count(*) from addrline where regexp_like(text, 'r$' );
Consider the following string which is a C fragment in a file:
strcat(errbuf,errbuftemp);
I want to replace errbuf (but not errbuftemp) with the prefix G-> plus errbuf. To do that successfully, I check the character after and the character before errbuf to see if it's in a list of approved characters and then I perform the replace.
I created the following Ruby file:
line = " strcat(errbuf,errbuftemp);"
item = "errbuf"
puts line.gsub(/([ \t\n\r(),\[\]]{1})#{item}([ \t\n\r(),\[\]]{1})/, "#{$1}G\->#{item}#{$2}")
Expected result:
strcat(G->errbuf,errbuftemp);
Actual result
strcatG->errbuferrbuftemp);
Basically, the matched characters before and after errbuf are not reinserted back with the replace expression.
Anyone can point out what I'm doing wrong?
Because you must use syntax gsub(/.../){"...#{$1}...#{$2}..."} or gsub(/.../,'...\1...\2...').
Here was the same problem: werid, same expression yield different value when excuting two times in irb
The problem is that the variable $1 is interpolated into the argument string before gsub is run, meaning that the previous value of $1 is what the symbol gets replaced with. You can replace the second argument with '\1 ?' to get the intended effect. (Chuck)
I think part of the problem is the use of gsub() instead of sub().
Here's two alternates:
str = 'strcat(errbuf,errbuftemp);'
str.sub(/\w+,/) { |s| 'G->' + s } # => "strcat(G->errbuf,errbuftemp);"
str.sub(/\((\w+)\b/, '(G->\1') # => "strcat(G->errbuf,errbuftemp);"