How I would determine if a string contains multiple substrings?

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I'd like to know if a string has multiple substrings (e.g, words) in it.
For example:
myString = "This has some words in it.";
I would want to know if that string has "This" AND "some". I know I can use "contains" to look for individual substrings, but I want to know if ALL substrings are in a string.

Accepted Answer

Pat Canny
Pat Canny on 23 Feb 2023
Edited: Pat Canny on 4 Aug 2023
Here is one way to do this using arrayfun:
myString = "This has some words in it.";
subStrings = ["This","some"];
hasAllSubstrings = all(arrayfun(@(substr) contains(myString, substr, 'IgnoreCase', true), subStrings))
  3 Comments
Pat Canny
Pat Canny on 11 Nov 2023
I think pattern may help you. Below is a simple example, but you can get fairly fancy with it.
testString1 = "ARRAY[";
testString2 = "ARRAY[something]";
testString3 = "ARRAY[]";
patternToMatch = "ARRAY[" + lettersPattern(3,10) + "]";
stringArray = [testString1;testString2;testString3];
isMissingPattern = arrayfun(@(str) ~contains(str, patternToMatch), stringArray)
isMissingPattern = 3×1 logical array
1 0 1
Ludo Houben
Ludo Houben on 16 Nov 2023
Hi @Pat Canny, thanks for your reply. I'm going to 'play' with this. Thank you.

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More Answers (3)

Bruno Luong
Bruno Luong on 4 Aug 2023
Edited: Bruno Luong on 4 Aug 2023
myString = "This has some words in it.";
subStrings = ["This","some"];
hasAllSubstrings = isequal(regexp(myString, subStrings, 'once', 'match'), subStrings)
hasAllSubstrings = logical
1

Les Beckham
Les Beckham on 23 Feb 2023
Edited: Les Beckham on 23 Feb 2023
myString = "This has some words in it.";
if contains(myString, "This") && contains(myString, "some")
disp Yes
else
disp No
end
Yes
  1 Comment
Pat Canny
Pat Canny on 23 Feb 2023
Yep, I also tried that. It works fine for two substrings, but what if there are several?

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Steven Lord
Steven Lord on 10 Nov 2023
myString = "This has some words in it.";
s = split(myString)
s = 6×1 string array
"This" "has" "some" "words" "in" "it."
whichWordsAreIn = ismember(["some"; "in"], s)
whichWordsAreIn = 2×1 logical array
1 1
allWordsIn = all(whichWordsAreIn)
allWordsIn = logical
1
You can combine this into one command if you want; I showed temporary variables to illustrate each step. For exclusions you want to wrap the ismember call in ~any() instead of all.
  2 Comments
Stephen23
Stephen23 on 16 Nov 2023
Edited: Stephen23 on 16 Nov 2023
myString = "This has some words in it.";
s = split(myString)
s = 6×1 string array
"This" "has" "some" "words" "in" "it."
whichWordsAreIn = ismember(["some"; "it"], s) % what happend to "it" ?
whichWordsAreIn = 2×1 logical array
1 0
Steven Lord
Steven Lord on 16 Nov 2023
I neglected to remove punctuation from the string before splitting it. The isstrprop function could help with this (though you'd have to be careful with punctuation included as part of a word, like "you'd" as I wrote earlier in this phrase.)
The accepted answer has a similar problem, if you change the text to be examined to include a word that contains as part of it one of the substrings being searched for.
myString = "This has something words in it.";
subStrings = ["This","some"]; % myString has "something", does that match "some"?
hasAllSubstrings = all(arrayfun(@(substr) contains(myString, substr, 'IgnoreCase', true), subStrings))
hasAllSubstrings = logical
1
For more general cases and processing lots of data, you may want to use the functionality for analyzing text data provided in Text Analytics Toolbox.

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