extract - Extract substrings from strings - MATLAB (original) (raw)

Extract substrings from strings

Since R2020b

Syntax

Description

[newStr](#mw%5F92b33e21-ed9e-4f0e-9c4f-c1a36c6631a8) = extract([str](#mw%5F6f9c458d-4360-47aa-b8c8-fc07eb1070b0%5Fsep%5Fbu4l86d-str),[pat](#mw%5F6b932a41-2bad-4590-9a16-939009af1565)) returns any substrings in str that match the pattern specified bypat.

If str is a string array or a cell array of character vectors, then the function extracts substrings from each element of str. Ifpat is an array, then the function matches against multiple patterns.

example

[newStr](#mw%5F92b33e21-ed9e-4f0e-9c4f-c1a36c6631a8) = extract([str](#mw%5F6f9c458d-4360-47aa-b8c8-fc07eb1070b0%5Fsep%5Fbu4l86d-str),[pos](#mw%5Fbcbf7a33-8948-4317-9107-24f3ab371c63)) returns the character in str at the position specified bypos.

example

Examples

collapse all

Create a string array that contains addresses. Each address ends with a US ZIP code.

str = ["73 Beacon St., Boston, MA, 02116"; "1640 Riverside Dr., Hill Valley, CA, 92530"; "138 Main St., Cambridge, MA, 02138"]

str = 3×1 string "73 Beacon St., Boston, MA, 02116" "1640 Riverside Dr., Hill Valley, CA, 92530" "138 Main St., Cambridge, MA, 02138"

Create a pattern that matches any sequence of digits.

pat = pattern Matching:

digitsPattern

Use it to extract all sequences of digits from the addresses.

newStr = extract(str,pat)

newStr = 3×2 string "73" "02116" "1640" "92530" "138" "02138"

The digitsPattern pattern matches street numbers, apartment numbers, and ZIP codes. To match only ZIP codes, create a pattern that matches a sequence of digits at the end of an address.

pat = digitsPattern + textBoundary

pat = pattern Matching:

digitsPattern + textBoundary

Extract the ZIP codes.

newStr = extract(str,pat)

newStr = 3×1 string "02116" "92530" "02138"

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

Create a string.

str = "All's well that ends well"

str = "All's well that ends well"

Extract the first character in the string.

Extract the last character.

extract(str,strlength(str))

Input Arguments

collapse all

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

Search pattern, specified as one of the following:

• String array
• Character vector
• Cell array of character vectors
• pattern array

Position, specified as a numeric array.

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

Output Arguments

collapse all

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

If str is a string array, then newStr is also a string array. Otherwise, newStr is a cell array of character vectors.

Extended Capabilities

expand all

Theextract 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.

For code generation, the input arguments must be a:

• Character vector or cell array of character vectors for input textstr.
• Character vector or cell array of character vectors for search patternpat

Version History

Introduced in R2020b

expand all

You can generate C/C++ code for this function.