I want to extract a set of characters between "u1=" and the first semi-colon using a regex. For instance, given the following string: id=1w54;name=nick;u1=blue;u2=male;u3=ohio;u5=
The desired regex output should be just blue.
I tested (?<=u1=)[^;]* on https://regex101.com and it works. However, when I run this in BigQuery, using regexp_extract(string, '(?<=u1=)[^;]*') , I get an error that reads "Cannot parse regular expression: invalid perl operator: (?<"
I'm confused why this isn't working in BQ. Any help would be appreciated.
You can use regexp_extract() like this:
regexp_extract(string, 'u1=([^;]+)')
Related
I am fairly new to teradata, but I was trying to understand how to use REGEXP_SUBSTR
For example I have the following cell value = ABCD^1234567890^1
How can I extract 1234567890
What I attempted to do is the following:
REGEXP_SUBSTR(x, '(?<=^).*?(?=^)')
But this didnt seem to work.
Can anyone help?
It might (or might not) be possible to use REGEXP_SUBSTR() to handle this, but you would need to use a capture group. An alternative here would be to do a regex replacement instead:
SELECT x, REGEXP_REPLACE(x, '^.*?\^|\^.*$', '') AS output
FROM yourTable;
The regex pattern used here matches:
^.*?\^ everything from the start to the first ^
| OR
\^.*$ everything from the second ^ to the end
We then replace with empty string to remove the content being matched.
I am having a deep dilemma in hive. My data set in Hive looks like this:
##214628##564#7576#7876
#12771#242###256823
###3264###7236473####3
In each instance, I want to print only the first string after the #. So the output should be something like this:
214628
12771
3264
I tried using the reg_extract function, but alas I am getting only NULL values. Since hive doesn't support reg_substr, the following synatax doesn't work:
to_number(trim(regexp_substr(col_name,'[^#]+',1,1)))
Any suggestions are wecome!
You can use regexp_replace and then substr combination.
First remove all multiple occurrences of # from the string using regexp_replace().
regexp_replace(col,'#+','#') -- for data '#####123##' this will produce '#123#'
Then remove first # using substr. And then use instr to fetch everything starting from first till #.
substr(substr(str,2),1, instr(substr(str,2),'#')-1) this will produce '123'
You can see whole sql below.
select substr(substr(str,2),1, instr(substr(str,2),'#')-1) as result
from (
SELECT regexp_replace('#####123##','#+','#') as str) a
I assumed you always have # in the beginning. if you just add if left(str,1)='#'... and handle according to the data.
I'm fairly new to coding and I was wondering if you could give me a hand writing some regular expression for BigQuery SQL.
Basically I would like to extract everything before the bar sign "|" for one of my column.
Example:
Source string:
bla-BLABLA-cid=123456_sept1220_blabla--potato-Blah|someMore_string_stuff-IDontNeed
Desired output:
bla-BLABLA-cid=123456_sept1220_blabla--potato-Blah
I thought about using the REGEXP_EXTRACT(string, delimiter) function but I'm totally unable to write some regex (LOL). Therefore I had a look over Stack, and have found stuff like:
SELECT REGEXP_EXTRACT( String_Name , "\S*\s*\|" ) ,
# or
SELECT REGEXP_EXTRACT( String_Name , '.+?(?=|)')
But every time I get error messages like " invalid perl operator: (?= " or "Illegal escape space"
Would you have any suggestions on why I get these messages and/or how could I proceed to extract these strings?
Many many thanks in advance <3
You can use SPLIT instead:
SELECT SPLIT("bla-BLABLA-cid=123456_sept1220_blabla--potato-Blah|someMore_string_stuff-IDontNeed", "|")[OFFSET(0)]
Prefix the pattern string with r:
SELECT REGEXP_EXTRACT(String_Name, r'\S*\s*\|')
This is the syntax for a raw string constant. You can review what this means in the documentation.
In Bigquery, I am trying to find a way to extract particular segments of a string based on how many dashes come before it. The number of total dashes in the string will always be the same. For example, I could be looking for the string after the second dash and before the third dash in the following string:
abc-defgh-hij-kl-mnop
Currently, I am using the following regex to extract, which counts the dashes from the back:
([^-]+)(?:-[^-]+){2}$
The problem is that if there is nothing in between the dashes, the regex doesn't work. For example, something like this returns null:
abc-defgh-hij--mnop
Is there a way to use regex to extract a string after a certain number of dashes and cut it off before the subsequent dash?
Thank you!
Below is for BigQuery Standrd SQL
The simplest way in your case is to use SPLIT and OFFSET as in below example
SELECT SPLIT(str, '-')[OFFSET(3)]
above will return empty string for abc-defgh-hij--mnop
to prevent error in case of calling non-existing element - better to use SAFE_OFFSET
SELECT SPLIT(str, '-')[SAFE_OFFSET(3)]
In pig script, I would like to find a way to escape the delimiter character in my data so that it doesn't get interpreted as extra columns. For example, if I'm using colon as a delimiter, and I have a column with value "foo:bar" I want that string interpreted as a single column without having the loader pick up the comma in the middle.
You can try http://pig.apache.org/docs/r0.12.0/func.html#regex-extract-all
A = LOAD 'somefile' AS (s:chararray);
B = FOREACH A GENERATE FLATTEN(REGEX_EXTRACT_ALL(s, '(.*) : (.*)'));
The regex might have to be adapted.
It seems Pig takes the Input as the string its not so intelligent to identify how what is data or what is not.
The pig Storage works on the Strong Tokenizer. So if u want to do something like
a = LOAD '/abc/def/file.txt' USING PigStorage(':');
It doesn't seems to be solving your problem. But if we can write our own PigStorage() Method possibly we could come across some solution.
I will try posting the Code to resolve this.
you can use STRSPLIT(string, regex, limit); for the column split based on the delimiter.