使用python获取正则表达式匹配周围的文本

Question

I have a todo.txt list like this, separated by newlines:

(D) 2015-02-18 XDA Ultimate guide to +Tasker @Phone @Computer
2015-02-18 Redesign the business card for +RepairWork @Computer
(A) 2015-02-17 +Study how to +Ask questions @Computer @Phone
(B) 2015-03-25 Update +LaundryTimer W/ new popup design +Tasker

And I have the regex to capture the +Projects and @Contexts:

## Projects
project_matches = re.findall('[+]\D\w+',todo_list)
print list(set(project_matches))

## Contexts
context_matches = re.findall('[@][A-Z]\w+',todo_list)
print list(set(context_matches))

But I would also like to quickly and efficiently capture each task and group by +Project or @Context.

For example, here is the desired output:

Phone:

(A) 2015-02-17 +Study how to +Ask questions @Computer @Phone
(D) 2015-02-18 XDA Ultimate guide to +Tasker @Phone @Computer

Computer:

(D) 2015-02-18 XDA Ultimate guide to +Tasker @Phone @Computer
2015-02-18 Redesign the business card for +RepairWork @Computer

Tasker:

(D) 2015-02-18 XDA Ultimate guide to +Tasker @Phone @Computer
(B) 2015-03-25 Update +LaundryTimer W/ new popup design +Tasker

Etc...

I also have the Regex to capture the task when it finds a Project or Context, but I don't know if it helps: (.*)(?=[+]\\D\\w+)(.*)

Answer 1

You could build some dictionaries. defaultdict makes it easier to start each item with a list .

import collections
projects = collections.defaultdict(list)
contexts = collections.defaultdict(list)
with open('todo_list.txt') as todo_list:
    for line in todo_list:
        for item in re.findall(r'[+]\D\w+', line):
            projects[item].append(line)
        for item in re.findall(r'[@][A-Z]\w+', line):
            contexts[item].append(line)

If you've already read the whole file into a single string, use splitlines() to iterate over each line:

import collections
projects = collections.defaultdict(list)
contexts = collections.defaultdict(list)
for line in todo_list.splitlines():
    for item in re.findall(r'[+]\D\w+', line):
        projects[item].append(line)
    for item in re.findall(r'[@][A-Z]\w+', line):
        contexts[item].append(line)

Answer 2

You can grab a whole line where a given word occurs using ^.*word.*$

Meaning: From the start of the string ^ match any character . any number of times * then match a word. Match any character multiple times again .* until the end of the line $

To accomplish your task you could do something like

tasks = re.findall(r"(^.*?%s.*?$)" % context, todo_list, re.MULTILINE)

where context is the word you're looking for (Phone, Computer, Tasker and so on)

Edit: the re.MULTILINE makes re matches in every line. It acts like the g modifier. You can see my example in action here: https://regex101.com/r/gS2yN9/1