How to extract dot(.) ended sentence?

Question

I need to extract sentence ends with dot '.', but don't extract sentence ends in ' ...' (blank and three dots).

Example:

I love you.
I love you too ...

I want to match first sentence not second.

i image python style pseudo code:

for string in strings:
    checker1 = (string == .)
    if checker:
        checekr2 = (prev_string(string) != blank)
        if checker2:
            extract_all_strings()
        else:
            pass
    else:
        pass

but I can't image regular expression code.

regex101.com is a wonderful tool: https://regex101.com/r/PmoiR6/1 — Micha Wiedenmann, Nov 26 '18 at 14:16
It looks like you are using Python to split text into sentences. Use NLTK. See [Tokenize a paragraph into sentence and then into words in NLTK](https://stackoverflow.com/a/37605851/3832970). — Wiktor Stribiżew, Nov 26 '18 at 14:24

score 1 · Answer 1 · answered Nov 26 '18 at 14:18

1

You can use (?<! \.\.)\.$, see the demo.

answered Nov 26 '18 at 14:18

Micha Wiedenmann

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I have to extract all sentence when pattern is matched. your solution is only extract dot(.) but your answer give me insight of regex. thank you!! – gukwon Nov 26 '18 at 15:19

Poul Bak · Accepted Answer · 2018-11-27T18:42:25.190

1

You can use the following regex:

[\w ]+\.(?!\.)

It matches one or more either Word character or Space, then it use a neagative look ahead to make sure there's only one dot.

edited Nov 27 '18 at 18:42

answered Nov 26 '18 at 14:42

Poul Bak

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thank you for your kind answer. it's really fantastic solution in my case. in fact, I should consider this pattern surrounded by other sentences. your solution is perfect!! – gukwon Nov 26 '18 at 15:15

Nikolas Charalambidis · Answer 3 · 2018-11-26T14:50:43.437

Here you go with a very simple Regex:

[\w ]+\.$

Test the solution on Regex101.

[\w ] is a group of allowed characters, where \w stands for any character from [a-zA-Z0-9_] and stands for space itself.
[\w ]+ where + means that there the characters from the group described in the point above might appear between one and unlimited times.
\. is the dot itself which must be escaped, otherwise the dot . matches any character.
$ stands for the end of a string.

This together assures that only a sentence ending with exactly one dot will be caught.

Another and less strict approach might be allow anything, where the 2nd character from the end is not a dot and the last one is a dot (Regex101).

.+[^\.]\.$

thank you for your detail answer. your answer has given me a better understanding of regular expression. really appreciate — gukwon, Nov 26 '18 at 15:17

How to extract dot(.) ended sentence?

3 Answers3