python r 正则表达式
    English Answer:
    What is Regular Expression in Python and R?
    Regular expressions (regex) are a powerful tool for pattern matching. They are used to search and manipulate strings, and can be used to perform a wide variety of tasks, from simple text substitution to complex data validation.
    Regexes are written in a special syntax that uses a variety of characters to represent patterns. For example, the following regex matches any string that contains the word "dog":
    dog.
    This regex can be used to find all occurrences of the word "dog" in a string, or to replace all occurrences of the word "dog" with another word.
    Regexes can be used in both Python and R. In Python, the `re` module provides a set of f
unctions for working with regexes. In R, the `stringr` package provides a set of functions for working with regexes.
    How to Use Regular Expressions in Python.
    To use regular expressions in Python, you can use the `re` module. The `re` module provides a set of functions for working with regexes, including:
    `repile()`: Compiles a regular expression into a pattern object.
    `re.match()`: Attempts to match the regular expression pattern to the beginning of a string.
    `re.search()`: Attempts to match the regular expression pattern anywhere in a string.
    `re.findall()`: Finds all occurrences of the regular expression pattern in a string.
    `re.sub()`: Substitutes all occurrences of the regular expression pattern in a string with a replacement string.
    For example, the following code uses the `re` module to find all occurrences of the word "dog" in a string:
    import re.
    string = "The dog is a good boy."
    pattern = repile("dog")。
    matches = pattern.findall(string)。
    print(matches)。
    This code will print the following output:
    ['dog']
    How to Use Regular Expressions in R.
    To use regular expressions in R, you can use the `stringr` package. The `stringr` packag
e provides a set of functions for working with regexes, including:
python正则表达式匹配小数    `str_detect()`: Tests whether a string matches a regular expression pattern.
    `str_match()`: Attempts to match the regular expression pattern to the beginning of a string.
    `str_search()`: Attempts to match the regular expression pattern anywhere in a string.
    `str_findall()`: Finds all occurrences of the regular expression pattern in a string.
    `str_replace()`: Substitutes all occurrences of the regular expression pattern in a string with a replacement string.