replace

Find and replace one or more substrings

Syntax

newStr = replace(str,old,new)

Description

newStr = replace(str,old,new) replaces all occurrences of the substring old with new. If old contains multiple substrings, then new either must be the same size as old, or must be a single substring.

Examples

Replace Substring in String Array

Replace placeholder text in a list of file names.

Create a string array.

str = ["<ROOT_DIR>\MyData\data.tar.gz";
       "<ROOT_DIR>\MyScripts\cleandata.m";
       "<ROOT_DIR>\MyScripts\preprocess.m";
       "<ROOT_DIR>\MyScripts\publishResults.m"]

str = 4×1 string
    "<ROOT_DIR>\MyData\data.tar.gz"
    "<ROOT_DIR>\MyScripts\cleandata.m"
    "<ROOT_DIR>\MyScripts\preprocess.m"
    "<ROOT_DIR>\MyScripts\publishResults.m"

Replace <ROOT_DIR> with a string that is the name of a file path.

old = "<ROOT_DIR>";
new = "C:\MyProject";
newStr = replace(str,old,new)

newStr = 4×1 string
    "C:\MyProject\MyData\data.tar.gz"
    "C:\MyProject\MyScripts\cleandata.m"
    "C:\MyProject\MyScripts\preprocess.m"
    "C:\MyProject\MyScripts\publishResults.m"

Replace Substrings That Match Pattern

Since R2020b

Create a string that includes a phone number.

str = "Hide the numbers in: [phone]"

str = 
"Hide the numbers in: [phone]"

Create a pattern that matches a digit using the digitsPattern function.

pat = digitsPattern(1)

pat = pattern
  Matching:

    digitsPattern(1)

Replace all digits with a "#" character.

newStr = replace(str,pat,"#")

newStr = 
"Hide the numbers in: (###) ###-####"

Create another pattern that matches only phone numbers.

pat = "(" + digitsPattern(3) + ") " + digitsPattern(3)  + "-" + digitsPattern(4)

pat = pattern
  Matching:

    "(" + digitsPattern(3) + ") " + digitsPattern(3) + "-" + digitsPattern(4)

Replace a phone number in a string that also has another number.

str = "12 calls made to: [phone]";
newStr = replace(str,pat,"(###) ###-####")

newStr = 
"12 calls made to: (###) ###-####"

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

Replace Multiple Substrings

Replace carriage returns with newline characters.

Create a string array.

str = ["Submission Date: 11/29/15\r";
       "Acceptance Date: 1/20/16\r";
       "Contact: [e-mail]\r\n"]

str = 3×1 string
    "Submission Date: 11/29/15\r"
    "Acceptance Date: 1/20/16\r"
    "Contact: [e-mail]\r\n"

Replace the carriage returns.

old = {'\r\n','\r'};
new = '\n';
newStr = replace(str,old,new)

newStr = 3×1 string
    "Submission Date: 11/29/15\n"
    "Acceptance Date: 1/20/16\n"
    "Contact: [e-mail]\n"

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.

old — Substring to replace

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

Substring to replace, specified as one of the following:

• String array

• Character vector

• Cell array of character vectors

• pattern array (since R2020b)

new — New substring

string array | character vector | cell array of character vectors

New substring, specified as a string array, character vector, or cell array of character vectors.

Tips

• To perform multiple replacements for overlapping patterns, use the strrep function.

Extended Capabilities

Tall Arrays

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

The replace function fully supports tall arrays. For more information, see Tall Arrays.

C/C++ Code Generation

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

Usage notes and limitations:

• str, old, and new 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™.

This function fully supports distributed arrays. For more information, see Run MATLAB Functions with Distributed Arrays (Parallel Computing Toolbox).

Version History

Introduced in R2016b