Extracting digits from string in QGIS

Question

I have a string field that I want to extract only the digits example: 1,500 m2 -> 1500

example

I've tried with regexp_substr("location", '(\\d*)') to remove all after the blank space, but I need also the ones that have a comma to only extract the digits, the first two rows work fine for me, but the two after doesn't (1,500 M2 and 1,456 m2)

Answer 1

Another regex expression to use is the following:

 regexp_substr("FieldName",'\\d,+\\d+|\\d+')

Substitute "FieldName" with the name of the field that you want to extract the digits from. "descriptio" in your case.

The above will extract digits with comma or digits without comma.

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• Juan Millan: Thank you!, this worked, but I realized I had blank spaces as well besides commas, is there an expression to solve that too?
• ahmadhanb: @JuanMillan I have not try this but you can give it a try: regexp_substr("FieldName",'\\d , \\d+|\\d,+\\d+|\\d+')

Answer 2

Probably a bit old-fashion approach but also gives a desired output using the follwoing expression

to_int(replace(left("text", regexp_match("text",' ') - 1), ',', ''))

example

Answer 3

An elegant way to remove 1) the string 'M2' plus 2) all characters except numbers is this epression. Like this, you remove commas, letters, all whitespaces etc., but keep all number (except the 2 in M2):

regexp_replace (Elev,'(M2|[^0-9])','')

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To match uppercase M2 as well as lowercase m2, instead of (M2| use (M|m)2|:

regexp_replace (Elev,'((M|m)2|[^0-9])','')

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Answer 4

Try using the regular expression provided in this answer.

regexp_substr( "location", '\b\d[\d,.]*\b' )

Answer 5

Another more general solution:

regexp_replace("location",'\\b(\\d+)[.,]?(\\d*)\\b.+','\1円\2円')

... and many other regex here: https://stackoverflow.com/questions/12117024/decimal-number-regular-expression-where-digit-after-decimal-is-optional

• bixb0012: Although a valid regular expression, it will not work as-is with regex_replace - QGIS Documentation because "Backslash characters must be double escaped...."
• christoph: @bixb0012 you are absolutely right... I changed my answer