extractAfter

Extract substrings after specified positions

Syntax

newStr = extractAfter(str,pat)

newStr = extractAfter(str,pos)

Description

newStr = extractAfter(str,pat) extracts the substring that begins after the substring specified by pat and ends with the last character of str. If pat occurs multiple times in str, then newStr is str from the first occurrence of pat to the end.

If str is a string array or a cell array of character vectors, then extractAfter extracts substrings from each element of str. The output argument newStr has the same data type as str.

newStr = extractAfter(str,pos) extracts the substring that begins after the position specified by pos and ends with the last character of str.

Examples

Select Text After Substring

Create string arrays and select text that occurs after substrings.

str = "The quick brown fox"

str = 
"The quick brown fox"

Extract the substring that occurs after the substring "quick ". The extractAfter function selects the new text but does not include "quick " in the output.

newStr = extractAfter(str,"quick ")

newStr = 
"brown fox"

Create a new string array from the elements of a string array. When you specify different substrings as positions, they must be contained in a string array or a cell array that is the same size as the input string array.

str = ["The quick brown fox jumps";"over the lazy dog"]

str = 2×1 string
    "The quick brown fox jumps"
    "over the lazy dog"

newStr = extractAfter(str,["quick ";"the "])

newStr = 2×1 string
    "brown fox jumps"
    "lazy dog"

You also can specify one substring as a position that is applied to all elements of the input string array.

Extract File Name After Path Using Pattern

Since R2020b

Create a string array of file names, including full paths.

str = ["C:\Temp\MyReport.docx";
       "C:\Data\Experiment1\Trial1\Sample1.csv";
       "C:\Temp\Slides.pptx"]

str = 3×1 string
    "C:\Temp\MyReport.docx"
    "C:\Data\Experiment1\Trial1\Sample1.csv"
    "C:\Temp\Slides.pptx"

To extract the file names, first create a pattern that matches a full path, and then extract what comes after that pattern.

A full path can have several levels, each consisting of any text followed by a "\" character. So start by creating a pattern that matches one level.

level = wildcardPattern + "\"

level = pattern
  Matching:

    wildcardPattern + "\"

Then, create a pattern that matches a full path, containing any number of levels.

pat = asManyOfPattern(level)

pat = pattern
  Matching:

    asManyOfPattern(wildcardPattern + "\")

Finally, call extractAfter.

filenames = extractAfter(str,pat)

filenames = 3×1 string
    "MyReport.docx"
    "Sample1.csv"
    "Slides.pptx"

For a list of functions that create pattern objects, see pattern.

Select Substrings After Position

Create strings after specified positions.

str = "Edgar Allen Poe"

str = 
"Edgar Allen Poe"

Select the substring after the 12th character.

newStr = extractAfter(str,12)

newStr = 
"Poe"

Select substrings from each element of a string array. When you specify different positions with numeric arrays, they must be the same size as the input string array.

str = ["Edgar Allen Poe";"Louisa May Alcott"]

str = 2×1 string
    "Edgar Allen Poe"
    "Louisa May Alcott"

newStr = extractAfter(str,[12;11])

newStr = 2×1 string
    "Poe"
    "Alcott"

Select substrings from each element and specify the same position.

newStr = extractAfter(str,6)

newStr = 2×1 string
    "Allen Poe"
    " May Alcott"

Select Text After Position in Character Vector

Create a character vector. Then create new character vectors that are substrings of chr.

chr = 'peppers and onions'

chr = 
'peppers and onions'

Select text after the 12th position.

newChr = extractAfter(chr,12)

newChr = 
'onions'

Select text after a substring.

newChr = extractAfter(chr,'and ')

newChr = 
'onions'

Input Arguments

str — Input text

string array | character vector | cell array of character vectors

Input text, specified as a string array, character vector, or cell array of character vectors.

pat — Text or pattern that marks start position

string array | character vector | cell array of character vectors | pattern array (since R2020b)

Text or pattern in str that marks the start position for extracted text, specified as one of the following:

• String array

• Character vector

• Cell array of character vectors

• pattern array (since R2020b)

The extractAfter function excludes pat from the substring that is extracted.

If str is a string array or cell array of character vectors, then you can extract substrings from every element of str. You can specify that the substrings either all have the same start or have different starts in each element of str.

• To specify the same start, specify pat as a character vector, string scalar, or pattern object.

• To specify different starts, specify pat as a string array, cell array of character vectors, or pattern array.

pos — Start position

numeric array

Start position, specified as a numeric array. extractAfter excludes the character at pos from the extracted substring.

If str is a string array or cell array of character vectors, then pos can be a numeric scalar or numeric array of the same size as str.

Output Arguments

newStr — Output text

string array | character vector | cell array of character vectors

Output text, returned as a string array, character vector, or cell array of character vectors.

Extended Capabilities

Tall Arrays

Calculate with arrays that have more rows than fit in memory.

The extractAfter function supports tall arrays with the following usage notes and limitations:

• If pat is an array of pattern objects, the size of the first dimension of the array must be 1.

For more information, see Tall Arrays.

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

• str and pat must be a string scalar, a character vector, or a cell array containing not more than one character vector.

Thread-Based Environment

Run code in the background using MATLAB® backgroundPool or accelerate code with Parallel Computing Toolbox™ ThreadPool.

This function fully supports thread-based environments. For more information, see Run MATLAB Functions in Thread-Based Environment.

Distributed Arrays

Partition large arrays across the combined memory of your cluster using Parallel Computing Toolbox™.

Usage notes and limitations:

• pattern objects must be scalar.

For more information, see Run MATLAB Functions with Distributed Arrays (Parallel Computing Toolbox).

Version History

Introduced in R2016b