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startsWith

Determine if string starts with pattern

Syntax

TF = startsWith(str,pattern)
TF = startsWith(str,pattern,'IgnoreCase',true)

Description

example

TF = startsWith(str,pattern) returns 1 (true) if str starts with the specified pattern, and returns 0 (false) otherwise.

If pattern is an array containing multiple patterns, then startsWith returns 1 if it finds that str starts with any element of pattern.

example

TF = startsWith(str,pattern,'IgnoreCase',true) ignores case when determining if str starts with pattern.

Examples

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Create a string array that contains file names. Determine which file names start with the word data.

Starting in R2017a, you can create strings using double quotes instead of the string function.

str = ["abstract.docx","data.tar","code.m"; ...
       "data-analysis.ppt","results.ptx","summary.ppt"]
str = 2x3 string array
    "abstract.docx"        "data.tar"       "code.m"     
    "data-analysis.ppt"    "results.ptx"    "summary.ppt"

Return a logical array where the position of each element equal to 1 corresponds to the position of a string in str that starts with data.

pattern = "data";
TF = startsWith(str,pattern)
TF = 2x3 logical array
   0   1   0
   1   0   0

Display the file names that start with data. Index back into str using TF.

str(TF)
ans = 2x1 string array
    "data-analysis.ppt"
    "data.tar"

Create a string array that contains file names. Determine which file names start with either abstract or data.

Starting in R2017a, you can create strings using double quotes instead of the string function.

str = ["abstract.docx","data.tar.gz","mycode.m","results.ptx"]
str = 1x4 string array
    "abstract.docx"    "data.tar.gz"    "mycode.m"    "results.ptx"

pattern = ["abstract","data"];
TF = startsWith(str,pattern)
TF = 1x4 logical array
   1   1   0   0

Display the strings that start with either abstract or data. Index back into str using TF.

str(TF)
ans = 1x2 string array
    "abstract.docx"    "data.tar.gz"

Create a string array that contains file names. Determine which file names start with data, ignoring case.

Starting in R2017a, you can create strings using double quotes instead of the string function.

str = ["DATA.TAR.GZ","data.xlsx","SUMMARY.PPT","tmp.gz"]
str = 1x4 string array
    "DATA.TAR.GZ"    "data.xlsx"    "SUMMARY.PPT"    "tmp.gz"

pattern = "data";
TF = startsWith(str,pattern,'IgnoreCase',true)
TF = 1x4 logical array
   1   1   0   0

Display the strings that start with data. Index back into str using TF.

str(TF)
ans = 1x2 string array
    "DATA.TAR.GZ"    "data.xlsx"

Create a character vector that contains the name of a file. Determine if the name starts with different patterns.

chr = 'data-analysis.ppt'
chr = 
'data-analysis.ppt'
TF = startsWith(chr,'data')
TF = logical
   1

TF = startsWith(chr,'test')
TF = logical
   0

Input Arguments

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Input string.

Data Types: string | char | cell

Search pattern, specified as a string array, a character vector, or a cell array of character vectors.

Data Types: string | char | cell

Extended Capabilities

Introduced in R2016b

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