MATLAB Programming Fundamentals - MathWorks

Test for Empty Strings and Missing Values

String arrays can contain both empty strings and missing values. Empty strings contain

zero characters and display as double quotes with nothing between them (""). You can

determine if a string is an empty string using the == operator. The empty string is a

substring of every other string. Therefore, functions such as contains always find the

empty string within other strings. String arrays also can contain missing values. Missing

values in string arrays display as <missing>. To find missing values in a string array, use

the ismissing function instead of the == operator.

Test for Empty Strings

You can test a string array for empty strings using the == operator.

Starting in R2017a, you can create an empty string using double quotes with nothing

between them (""). Note that the size of str is 1-by-1, not 0-by-0. However, str contains

zero characters.

str = ""

str =

""

Create an empty character vector using single quotes. Note that the size of chr is 0-by-0.

The character array chr actually is an empty array, and not just an array with zero

characters.

chr = ''

chr =

0x0 empty char array

Create an array of empty strings using the strings function. Each element of the array

is a string with no characters.

str2 = strings(1,3)

str2 = 1x3 string array

"" "" ""

Test if str is an empty string by comparing it to an empty string.

Test for Empty Strings and Missing Values