Regex exact pattern matching with a variable

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I need to detect the exact patterns in text from the lst list but not when it is a part of other words. I know that I can use anchors to match exactly the pattern but it doesn't work with variables. Will appreciate your help!

lst = ['Test', 'Pink', 'Blue', 'Green']
text = 'Testing and Pink. Blue is my fav color. Greenwood is my name.'
def get_words_from_lst(text, lst):
    words = []        
    for word in lst:
        if r'{}'.format(word) in text:
            words.append(word)
    print(words)
get_words_from_lst(text, lst)

desired output: ['Pink', 'Blue']

Using Regex with boundaries (\b)

Demo:

import re
lst = ['Test', 'Pink', 'Blue', 'Green']
text = 'Testing and Pink. Blue is my fav color. Greenwood is my name.'
def get_words_from_lst(text, lst):
    #print([word for word in lst if re.search(r"\b"+word+r"\b", text)])   #Single line list comprehension 
    words = []
    for word in lst:
        if re.search(r"\b"+word+r"\b", text):
            words.append(word)
    print(words)
get_words_from_lst(text, lst)

Output:

['Pink', 'Blue']

Get exact match of a word using RegEx, I have never made a foray into regular expressions before, so this is all brand new to me. I want to search the string, see if an exact word is in  Here, regex is the command. We will see about optional switches later. Patterns are the rules as mentioned earlier. Search string is the actual string on which the regex is performed. Full match is any variable to hold the result of matched regex result. Submatch1 to SubMatchn are optional subMatch variable that holds the result of sub match patterns.

Split the text by non word characters \W. Then find the intersection of the two lists.

set(lst).intersection(re.split('\W', text))

Bash: exact match of a string with regex, You get a success because the regex matches on a portion of it. If you want an exact match, you need to anchor the pattern to the start and end  When you use the -match operator, an automatic variable called $matches contains the results of the match. If you have any sub expressions in your regex, those sub matches are also listed. If you have any sub expressions in your regex, those sub matches are also listed.

You can use str.join:

import re
lst = ['Test', 'Pink', 'Blue', 'Green']
text = 'Testing and Pink. Blue is my fav color. Greenwood is my name.' 
new_text = re.findall('|'.join(r'\b{}\b'.format(i) for i in lst), text)

Output:

['Pink', 'Blue']

Pattern Matching, (not match) operators are specified. in text paremeters of State and Event contexts it will match against anything; if it is not blank it must match the whole target text not replace variables which do not have a value. matching is case-​insensitive Regular expressions are similar to simple matching patterns but have many  Regular expressions are patterns used to match character combinations in strings. In JavaScript, regular expressions are also objects. These patterns are used with the exec() and test() methods of RegExp, and with the match(), matchAll(), replace(), search(), and split() methods of String. This chapter describes JavaScript regular expressions.

You can use a regex to split the letter groups (words) from punctuation then use a list comprehension:

>>> [word for word in re.split(r'[^a-zA-Z]',text) if word in lst]
['Pink', 'Blue']

Or, alternatively:

>>> [word for word in re.split(r'\W',text) if word in lst]
['Pink', 'Blue']

In either case, the support for unicode is limited if you use re.split. Python re module does not support [^\p{L}] that would allow a split on any non-letter unicode character.

You can also approach it as a filter and do:

>>> [word for word in lst if re.search(r'\b{}\b'.format(word), text)]
['Pink', 'Blue']

or

>>> filter(lambda w: re.search(r'\b{}\b'.format(w), text), lst)
['Pink', 'Blue']

But the first method would be faster if you have ascii only text. The second method does support unicode with proper flags.

Special pattern matching character operators, The simplest and very common pattern matching character operators is the . for any single character to match where a . is placed in a regular expression. Note that \w matches a single alphanumeric character, not a whole word. After a successful match the variable $1, $2, $3, are set on the same values as \1,\2,\3, . Following regex is used in Python to match a string of three numbers, a hyphen, three more numbers, another hyphen, and four numbers. Any other string would not match the pattern. \d\d\d-\d\d\d-\d\d\d\d. Regular expressions can be much more sophisticated. For example, adding a 3 in curly brackets ( {3}) after a pattern is like saying, “ Match

String-searching algorithm, In computer science, string-searching algorithms, sometimes called string-​matching algorithms, In particular, if a variable-width encoding is in use, then it may be slower to find the Nth character, perhaps Another more complex type of search is regular expression searching, where the user constructs a pattern of  Online regex tester, debugger with highlighting for PHP, PCRE, Python, Golang and JavaScript. Online regex tester and debugger: PHP, PCRE, Python, Golang and JavaScript Regular Reg Expressions Ex 101

Pattern matching, The regexp command takes a pattern, a string, and an optional match variable. It tests whether the string matches the pattern, returns 1 if there is a match and  if you have a the input password in a variable and you want to match exactly 123456 then anchors will help you: /^123456$/ in perl the test for matching the password would be something like

exact match in Perl, If the variable has 0 row(s) selected then i'm printing some text message else printing some other text The Best way in Perl to get an exactly exact match is to use the eq operator ( for strings ) or the == operator ( for numbers ), not a regex.