insertBefore

Insert strings before specified substrings

Syntax

newStr = insertBefore(str,pat,newText)

newStr = insertBefore(str,pos,newText)

Description

newStr = insertBefore(str,pat,newText) inserts newText into str before the substring specified by pat and returns the result as newStr. If pat occurs multiple times in str, then insertBefore inserts text before every occurrence of pat.

If str is a string array or a cell array of character vectors, then insertBefore inserts newText into each element of str. The output argument newStr has the same data type as str.

newStr = insertBefore(str,pos,newText) inserts the text specified by newText into str before the position specified by pos.

Examples

Insert Text Before Substring

Create string arrays and insert text before substrings.

You can create strings using double quotes.

str = "bread cheese wine"

str = 
"bread cheese wine"

Insert a comma before each space character in the string. The insertBefore function inserts text before each matching substring.

newStr = insertBefore(str," ",",")

newStr = 
"bread, cheese, wine"

Insert substrings into each element 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 str.

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

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

newStr = insertBefore(str,[" fox";" dog"],[" brown";" lazy"])

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

Insert Text Before File Names 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"

Insert a new folder name at the end of each path, just before the file name. To match the file names, create a pattern that matches the last "\" character and all remaining text to the end of a string. Use the wildcardPattern function to match all characters except "\" and the textBoundary function to match the end of the string. Then call insertBefore to insert the new folder name before the matching text.

pat = "\" + wildcardPattern("Except","\") + textBoundary

pat = pattern
  Matching:

    "\" + wildcardPattern("Except","\") + textBoundary

filenames = insertBefore(str,pat,"\20200601")

filenames = 3×1 string
    "C:\Temp\20200601\MyReport.docx"
    "C:\Data\Experiment1\Trial1\20200601\Sample1.csv"
    "C:\Temp\20200601\Slides.pptx"

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

Insert Substring Before Position

Create string arrays and specify positions to insert substrings.

You can create strings using double quotes.

str = "James Maxwell"

str = 
"James Maxwell"

Insert a substring before the seventh character.

newStr = insertBefore(str,7,"Clerk ")

newStr = 
"James Clerk Maxwell"

Insert substrings into 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 = ["James Maxwell";"Carl Gauss"]

str = 2×1 string
    "James Maxwell"
    "Carl Gauss"

newStr = insertBefore(str,[7;6],["Clerk ";"Friedrich "])

newStr = 2×1 string
    "James Clerk Maxwell"
    "Carl Friedrich Gauss"

Insert Text Before Position in Character Vector

Create a character vector and insert text before a specified position.

chr = 'mushrooms and onions'

chr = 
'mushrooms and onions'

Insert text before the tenth position.

newChr = insertBefore(chr,10,', peppers,')

newChr = 
'mushrooms, peppers, and onions'

Insert text before a substring.

newChr = insertBefore(chr,' and',', peppers,')

newChr = 
'mushrooms, peppers, and 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 end position

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

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

• String array

• Character vector

• Cell array of character vectors

• pattern array (since R2020b)

If str is a string array or cell array of character vectors, then you can insert text into every element of str. You can specify that the insertions either all have the same end or have different ends in each element of str.

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

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

pos — End position

numeric array

End position, specified as a numeric array.

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.

newText — Text to insert

string array | character vector | cell array of character vectors

Text to insert, specified as a string array, character vector, or cell array of character vectors.

If str is a string array or cell array of character vectors, then newText can be a character vector, string scalar, or a string array or cell 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. str and newStr have the same data type.

Extended Capabilities

Tall Arrays

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

The insertBefore 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, pat, and newText 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