Python regex single line flag

Considering the following text pattern,

#goals: the process report timestamp, eg. 2011-09-21 15:45:00 and the first two stats in succ. statistics line, eg: 1438 1439

input_text = '''
# Process_Name     ( 23387) Report at 2011-09-21 15:45:00.001    Type:  Periodic    #\n
some line 1\n
some line 2\n
some other lines\n
succ. statistics |     1438     1439  99 |   3782245    3797376  99 |\n
some lines\n
Process_Name     ( 23387) Report at 2011-09-21 15:50:00.001    Type:  Periodic    #\n
some line 1\n
some line 2\n
some other lines\n
succ. statistics |     1436     1440  99 |   3782459    3797523  99 |\n
repeat the pattern several hundred times...
'''

I got it working when iterating line to line,

def parse_file(file_handler, patterns):

    results = []
    for line in file_handler:
        for key in patterns.iterkeys():
            result = re.match(patterns[key], line)
            if result:
                results.append( result )

return results

patterns = {
    'report_date_time': re.compile('^# Process_Name\s*\(\s*\d+\) Report at (.*)\.[0-9]   {3}\s+Type:\s*Periodic\s*#\s*.*$'),
    'serv_term_stats': re.compile('^succ. statistics \|\s+(\d+)\s+   (\d+)+\s+\d+\s+\|\s+\d+\s+\d+\s+\d+\s+\|\s*$'),
    }
results = parse_file(fh, patterns)

returning

[('2011-09-21 15:40:00',),
('1425', '1428'),
('2011-09-21 15:45:00',),
('1438', '1439')]

but having a list of tuples output as my goal,

[('2011-09-21 15:40:00','1425', '1428'),
('2011-09-21 15:45:00', '1438', '1439')]

I tried several combos with the initial patterns and a lazy quantifier between them but can't figure out how to capture the patterns using a multiline REGEX

# .+?   Lazy quantifier "match as few characters as possible (all characters allowed) until reaching the next expression"
pattern = '# Process_Name\s*\(\s*\d+\) Report at (.*)\.[0-9]{3}\s+Type:\s*Periodic.*?succ. statistics) \|\s+(\d+)\s+(\d+)+\s+\d+\s+\|\s+\d+\s+\d+\s+\d+\s+\|\s'
regex = re.compile(pattern, flags=re.MULTILINE)

data = file_handler.read()    
for match in regex.finditer(data):
    results = match.groups()

How can I accomplish this ?

Summary: To match a pattern in a given text using only a single line of Python code, use the one-liner import re; print(re.findall(pattern, text)) that imports the regular expression library re and prints the result of the findall() function to the shell.

Python regex single line flag

Problem: Given a string and a regular expression pattern. Match the string for the regex pattern—in a single line of Python code!

Example: Consider the following example that matches the pattern 'F.*r' against the string 'Learn Python with Finxter'.

import re
s = 'Learn Python with Finxter'
p = 'F.*r'
# Found Match of p in s: 'Finxter'

Let’s dive into the different ways of writing this into a single line of Python code!

Exercise: Run the code. What’s the output of each method? Why does the output differ?

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  • Method 1: findall()
  • Method 2: search()
  • Method 3: match()
  • Method 4: fullmatch()
  • Where to Go From Here?

Method 1: findall()

The re.findall(pattern, string, flags=0) method returns a list of string matches. Read more in our blog tutorial.

# Method 1: findall()
import re; print(re.findall('F.*r', 'Learn Python with Finxter'))
# ['Finxter']

There’s no better way of importing the re library and calling the re.findall() function in a single line of code—you must use the semicolon A;B to separate the statements A and B.

The findall() function finds all occurrences of the pattern in the string.

The re.search(pattern, string, flags=0) method returns a match object of the first match. Read more in our blog tutorial.

# Method 2: search()
import re; print(re.search('F.*r', 'Learn Python with Finxter'))
# 

The search() function finds the first match of the pattern in the string and returns a matching object

Method 3: match()

The re.match(pattern, string, flags=0) method returns a match object if the regex matches at the beginning of the string. Read more in our blog tutorial.

# Method 3: match()
import re; print(re.match('.*F.*r', 'Learn Python with Finxter'))
# 

The match() function finds the match of the pattern at the beginning of the string and returns a matching object. In this case, the whole string matches, so the match object encloses the whole string.

Method 4: fullmatch()

The re.fullmatch(pattern, string, flags=0) method returns a match object if the regex matches the whole string. Read more in our blog tutorial.

# Method 4: fullmatch()
import re; print(re.fullmatch('.*F.*r.*', 'Learn Python with Finxter'))
#

The fullmatch() function attempts to match the whole string and returns a matching object if successful. In this case, the whole string matches, so the match object encloses the whole string.

Where to Go From Here?

Enough theory. Let’s get some practice!

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Python regex single line flag

While working as a researcher in distributed systems, Dr. Christian Mayer found his love for teaching computer science students.

To help students reach higher levels of Python success, he founded the programming education website Finxter.com. He’s author of the popular programming book Python One-Liners (NoStarch 2020), coauthor of the Coffee Break Python series of self-published books, computer science enthusiast, freelancer, and owner of one of the top 10 largest Python blogs worldwide.

His passions are writing, reading, and coding. But his greatest passion is to serve aspiring coders through Finxter and help them to boost their skills. You can join his free email academy here.

How do you use flags in regex Python?

M flag is used as an argument inside the regex method to perform a match inside a multiline block of text. Note: This flag is used with metacharacter ^ and $ . When this flag is specified, the pattern character ^ matches at the beginning of the string and each newline's start ( \n ).

What is Finditer in Python?

The finditer() function matches a pattern in a string and returns an iterator that yields the Match objects of all non-overlapping matches.

What is re I in Python?

A regular expression (or RE) specifies a set of strings that matches it; the functions in this module let you check if a particular string matches a given regular expression (or if a given regular expression matches a particular string, which comes down to the same thing).

How do you match a string in Python?

Steps of Regular Expression Matching.
Import the regex module with import re..
Create a Regex object with the re. compile() function. ... .
Pass the string you want to search into the Regex object's search() method. ... .
Call the Match object's group() method to return a string of the actual matched text..