Stringr Functions Overview
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Stringr Functions Overview

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Questions and Answers

What does str_detect do?

  • Extract substrings from a character vector.
  • Count the number of matches in a string.
  • Detect the presence of a pattern match in a string. (correct)
  • Find the first pattern match in a string.
  • What is the function of str_which?

    Find the indexes of strings that contain a pattern match.

    What does str_count do?

    Count the number of matches in a string.

    What is the purpose of str_locate?

    <p>Locate the positions of pattern matches in a string.</p> Signup and view all the answers

    What does str_sub accomplish?

    <p>Extract substrings from a character vector.</p> Signup and view all the answers

    What is str_subset used for?

    <p>Return only the strings that contain a pattern match.</p> Signup and view all the answers

    What does str_extract return?

    <p>Return the first pattern match found in each string, as a vector.</p> Signup and view all the answers

    What is achieved by using str_match?

    <p>Return the first pattern match found in each string, as a matrix with a column for each group in pattern.</p> Signup and view all the answers

    What does str_length indicate?

    <p>The width of strings (i.e., the number of characters).</p> Signup and view all the answers

    What is the function of str_pad?

    <p>Pad strings to constant width.</p> Signup and view all the answers

    What does str_trunc do?

    <p>Truncate the width of strings, replacing content with ellipsis.</p> Signup and view all the answers

    What is the purpose of str_trim?

    <p>Trim whitespace from the start and/or end of a string.</p> Signup and view all the answers

    What does str_replace accomplish?

    <p>Replace the first matched pattern in each string.</p> Signup and view all the answers

    What is the role of str_replace_all?

    <p>Replace all matched patterns in each string.</p> Signup and view all the answers

    What does str_to_lower do?

    <p>Convert strings to lower case.</p> Signup and view all the answers

    What does str_to_upper accomplish?

    <p>Convert strings to upper case.</p> Signup and view all the answers

    What is the function of str_to_title?

    <p>Convert strings to title case.</p> Signup and view all the answers

    What does str_c do?

    <p>Join multiple strings into a single string.</p> Signup and view all the answers

    What is achieved with str_dup?

    <p>Repeat strings times times.</p> Signup and view all the answers

    What does str_split_fixed do?

    <p>Split a vector of strings into a matrix of substrings.</p> Signup and view all the answers

    What is the use of str_split?

    <p>Return a list of substrings.</p> Signup and view all the answers

    What does glue::glue do?

    <p>Create a string from strings and expressions to evaluate.</p> Signup and view all the answers

    What is the purpose of glue::glue_data?

    <p>Use a data frame or list to create a string from strings and expressions to evaluate.</p> Signup and view all the answers

    What does str_order do?

    <p>Return the vector of indexes that sorts a character.</p> Signup and view all the answers

    What is the function of str_sort?

    <p>Sort a character vector.</p> Signup and view all the answers

    What does str_conv do?

    <p>Override the encoding of a string.</p> Signup and view all the answers

    What is str_view used for?

    <p>View HTML rendering of first regex match in each string.</p> Signup and view all the answers

    What does str_view_all do?

    <p>View HTML rendering of all regex matches.</p> Signup and view all the answers

    What is the purpose of str_wrap?

    <p>Wrap strings into nicely formatted paragraphs.</p> Signup and view all the answers

    Study Notes

    Stringr Functions Overview

    • str_detect: Identifies if a specified pattern exists within a string.
    • str_which: Returns indices of strings where a pattern match is found.
    • str_count: Tallies the occurrences of a pattern within a string.
    • str_locate: Pinpoints the exact locations of pattern matches in a string.
    • str_sub: Retrieves a substring from a character vector.

    String Filtering and Extraction

    • str_subset: Filters and returns only those strings that contain a specific pattern.
    • str_extract: Captures the first instance of a pattern found within each string, returning a vector.
    • str_match: Similar to str_extract but provides matches as a matrix, displaying different groups defined by parentheses in the pattern.

    String Manipulation Functions

    • str_length: Measures the length of strings in terms of character count.
    • str_pad: Expands a string's width by padding it with specified characters.
    • str_trunc: Reduces string size, truncating content with an ellipsis if necessary.
    • str_trim: Removes leading and trailing whitespace from strings.

    Substitution Functions

    • str_replace: Substitutes the first instance of a matched pattern in each string.
    • str_replace_all: Replaces every occurrence of a matched pattern throughout each string.

    Case Conversion Functions

    • str_to_lower: Transforms all characters in the string to lowercase.
    • str_to_upper: Converts all characters in the string to uppercase.
    • str_to_title: Modifies a string to title case, capitalizing the first letter of each word.

    String Joining and Repeating

    • str_c: Concatenates multiple strings into one.
    • str_dup: Duplicates a string a specified number of times.

    String Splitting

    • str_split_fixed: Divides a vector of strings into a matrix format based on occurrences of a pattern.
    • str_split: Breaks strings into a list of substrings, facilitating flexible manipulation.

    Advanced String Handling

    • glue::glue: Constructs strings from variables and expressions to evaluate inline.
    • glue::glue_data: Similar to glue but uses structures like data frames or lists for string construction.

    Sorting and Viewing Strings

    • str_order: Provides indices that would correctly sort a character vector.
    • str_sort: Organizes a character vector in ascending order.
    • str_conv: Adjusts the encoding of a given string.
    • str_view: Displays an HTML view of the first regex match found in each string.
    • str_view_all: Renders an HTML view of all regex matches appearing in the strings.

    Formatting Strings

    • str_wrap: Reformats strings into structured paragraphs for improved readability.

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    Description

    This quiz covers the essential functions of the Stringr package, including string detection, counting, extraction, and manipulation. Test your understanding of how to work with strings in R using specific functions like str_detect, str_extract, and str_length.

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