如何使用正则表达式和python在字符串中查找特定文本

Question

I have a text in every cell of a column, where i want to get some information from. In every cell i have detailed information about cars and i need to get the text from it. In my case these are the fuel and the CO2 information.

The string, that i get, looks like this:

cell 1 = 17.160 km, 80 kW (109 PS)Limousine, Autogas (LPG), Automatik, HU Neu, 2/3 Türenca. 5,0 l/100km (komb.), ca. 116 g CO₂/km (komb.)

cell 2 = EZ 10/2018, 12.900 km, 80 kW (109 PS)Limousine, Unfallfrei, Hybrid (Benzin/Elektro), Halbautomatik, HU Neu, ca. 5,9 l/100km (komb.), ca. 134 g CO₂/km (komb.) ... and so on

so i need the information from cell 1: 5,0 l/100 km and 116 g CO2/km

and from cell 2: 5,9 l/100km and 134 g CO2/km

I tried the following code examples, but nothing worked:

    pattern_z = re.compile("[a-z]+.?\s?[0-9]+\s?[a-z]?\s[A-Z]+")
    pattern_z = re.compile("^[ac]+\s?[CO]$")
    pattern_z = re.compile(r'[0-9]+.[g]?')
    

and after each "pattern_z" variable i tried

    co = pattern_z.search(i)
    cox = co.group()

but nothing worked.

I would appreciate every help.

Answer 1

Use

(\d+(?:,\d+)?\s*l/\d+km).*?(\d+\s?g\s*CO[₂2]/km)

See regex proof .

EXPLANATION

--------------------------------------------------------------------------------
  (                        group and capture to \1:
--------------------------------------------------------------------------------
    \d+                      digits (0-9) (1 or more times (matching
                             the most amount possible))
--------------------------------------------------------------------------------
    (?:                      group, but do not capture (optional
                             (matching the most amount possible)):
--------------------------------------------------------------------------------
      ,                        ','
--------------------------------------------------------------------------------
      \d+                      digits (0-9) (1 or more times
                               (matching the most amount possible))
--------------------------------------------------------------------------------
    )?                       end of grouping
--------------------------------------------------------------------------------
    \s*                      whitespace (\n, \r, \t, \f, and " ") (0
                             or more times (matching the most amount
                             possible))
--------------------------------------------------------------------------------
    l/                       'l/'
--------------------------------------------------------------------------------
    \d+                      digits (0-9) (1 or more times (matching
                             the most amount possible))
--------------------------------------------------------------------------------
    km                       'km'
--------------------------------------------------------------------------------
  )                        end of \1
--------------------------------------------------------------------------------
  .*?                      any character except \n (0 or more times
                           (matching the least amount possible))
--------------------------------------------------------------------------------
  (                        group and capture to \2:
--------------------------------------------------------------------------------
    \d+                      digits (0-9) (1 or more times (matching
                             the most amount possible))
--------------------------------------------------------------------------------
    \s?                      whitespace (\n, \r, \t, \f, and " ")
                             (optional (matching the most amount
                             possible))
--------------------------------------------------------------------------------
    g                        'g'
--------------------------------------------------------------------------------
    \s*                      whitespace (\n, \r, \t, \f, and " ") (0
                             or more times (matching the most amount
                             possible))
--------------------------------------------------------------------------------
    CO                       'CO'
--------------------------------------------------------------------------------
    [₂2]               any character of: '&', '#', '8', '3',
                             '2', '2', ';', '2'
--------------------------------------------------------------------------------
    /km                      '/km'
--------------------------------------------------------------------------------
  )                        end of \2

Python code :

import re

regex = r"(\d+(?:,\d+)?\s*l/\d+km).*?(\d+\s?g\s*CO[₂2]/km)"

test_str = "17.160 km, 80 kW (109 PS)Limousine, Autogas (LPG), Automatik, HU Neu, 2/3 Türenca. 5,0 l/100km (komb.), ca. 116 g CO₂/km (komb.)\n\nEZ 10/2018, 12.900 km, 80 kW (109 PS)Limousine, Unfallfrei, Hybrid (Benzin/Elektro), Halbautomatik, HU Neu, ca. 5,9 l/100km (komb.), ca. 134 g CO₂/km (komb.) ... and so on"

print (re.findall(regex, test_str))

Results : [('5,0\ l/100km', '116\ g CO₂/km'), ('5,9\ l/100km', '134\ g CO₂/km')]

Answer 2

You might use

\b\d+(?:,\d+)?(?:\s*l/\d+|\s*g\s+CO₂/)km\b

• \\b A word boundary
• \\d+(?:,\\d+)? Match 1+ digits and an optional decimal part
• (?: Non catpure group
  • \\s*l/\\d+ match l/ and 1+ digits
  • | Or
  • \\s*g\\s+CO₂/ match g , whitespace chars and CO₂/
• ) Close non capture group
• km\\b Match km and a word boundary to prevent a partial match

Regex demo

import re

strings = [
    '17.160 km, 80 kW (109 PS)Limousine, Autogas (LPG), Automatik, HU Neu, 2/3 Türenca. 5,0 l/100km (komb.), ca. 116 g CO₂/km (komb.)',
    'EZ 10/2018, 12.900 km, 80 kW (109 PS)Limousine, Unfallfrei, Hybrid (Benzin/Elektro), Halbautomatik, HU Neu, ca. 5,9 l/100km (komb.), ca. 134 g CO₂/km (komb.)'
    ]
pattern = r"\b\d+(?:,\d+)?(?:\s*l/\d+|\s*g\s+CO₂/)km\b"
for s in strings:
    print(re.findall(pattern, s))

Output

['5,0 l/100km', '116 g CO₂/km']
['5,9 l/100km', '134 g CO₂/km']