How to get the first sentence before a defined string with Regex

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I am doing some scraping and I want to scrape a certain part of a src element but not sure how to do this with regex. Are there any regex ninja's here who can help me?

srcset=" 150w, 300w, 600w, 1200w"

I want the first url before 1200w. So the outcome should be:

Why I need regex for this, the last element:

Thanks in advance and have a great weekend :)

First Sentence Regex, So much for Mr. Regex and his sentence matching. the word before the punctuation mark was, but that's going to get from a chunk of text. In regex, anchors are not used to match characters. Rather they match a position i.e. before, after, or between characters. To match start and end of line, we use following anchors: Caret (^) matches the position before the first character in the string. Dollar ($) matches the position right after the last character in the string. 2.


a = 'srcset=" 150w, 300w, 600w, 1200w"'

a = a.replace('srcset=', '').replace('"', '').split(',')
done = a[len(a)-1].strip().split(' ')[0]

Regex Tutorial, The caret ^ matches the position before the first character in the string. most regex engines discussed in this tutorial have the option to expand the meaning of � Say we want to extract the first sentence from the example String. This is quite easy to do using split: String[] sentences = text.split("\\."); Since the split method accepts a regex we had to escape the period character. Now the result is an array of 2 sentences. We can use the first sentence (or iterate through the whole array):

You can use this regex:


Regex Examples: Matching Whole Lines of Text That Satisfy Certain , Regular expression examples showing how you can match an entire line of text in a file entire lines in a search-and-replace in a text editor, or collect entire lines in an of the line before and after the match of our original regular expression John, we The first backreference will contain the word the line actually contains. The \K syntaxforces the regex engine to consider that any matched regex, before the \K form, is forgotten and that the final regex to match is, ONLY, the regex, located after the \K form. IMPORTANT: Due to the \K feature, included in the second S/R, you must use the Replace All button, exclusively.

Searching for r"600w, (.*) 1200w" , you Group 1 should return the url you are looking for.

Java regex extract string, java regex extract string Extract All Unique Words - Java task; Match Full Name - Java The main process of the algorithm is following Get the first 80 characters For the the number if it appears at the beginning of a line, with no characters before it. The pattern defined by the regular expression may match one or several� This is nearly exactly the same as the first regex, except that the sides are no longer matched, but just checked with a lookbehind and a lookahead. This works in .NET, PCRE (C, PHP, R, …), Java and Ruby (or Python with the regex module), but not in other engines as traditional lookbehind must have a fixed width (see Lookbehind: Fixed-Width

The pattern .+?(?=1200w) will match any character except a newline 1+ times until what is on the right is 1200.

To get a more specific match using a regex, you could use a capturing group:

\bsrcset="[^"]* (https?://\S+)\s+1200w"

Regex demo | Python demo

For example:

import re
regex = r'\bsrcset="[^"]* (https?://\S+)\s+1200w"'
test_str = """srcset=\" 150w, 300w, 600w, 1200w\""""

matches =, test_str)
if matches:


Using Regex for Text Manipulation in Python, text). The first parameter of the match function is the regex expression that Till now we have been using regex to find if a pattern exists in a string. Sometimes we have a sentence that starts or ends with a space, which is often not desirable. such as an apostrophe, results in a single character which has no meaning. My sentence must start with either one or more whitespaces/tabs. (tabs and spaces can be bunched together before any non-whitespace phrase of characters appears). Each word after the first must be separated by a whitespace. And yes, the sentence must end with a punctuation. – user1923 Dec 2 '13 at 4:19

I want to extract text before first comma (first and last name) from strings like: John Smith, RN, BSN, MS Thom Nev, MD Foo Bar, MD,RN Escaping regex string. 1407.

The tables are meant to serve as an accelerated regex course, and they are meant to be read slowly, one line at a time. On each line, in the leftmost column, you will find a new element of regex syntax. The next column, "Legend", explains what the element means (or encodes) in the regex syntax.

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