How I would determine if a string contains multiple substrings?

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.

Answer 1

[Pat Canny]

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))

[Ludo Houben]

Hi @Pat Canny

Is there a way to also exclude a string? So eg. if you want to search for missing parts in a variable declaration? I need something like

'ARRAY[' AND NOT ('..' OR ']')

As I want to include this in a 'cellfun' formula.

Thanks

Ludo

[Pat Canny]

Hi @Ludo Houben,

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]

Hi @Pat Canny, thanks for your reply. I'm going to 'play' with this. Thank you.

Answer 2

[Bruno Luong]

myString = "This has some words in it.";
subStrings = ["This","some"];

hasAllSubstrings = isequal(regexp(myString, subStrings, 'once', 'match'), subStrings)

hasAllSubstrings = logical
   1

Answer 3

[Les Beckham]

myString = "This has some words in it.";
if contains(myString, "This") && contains(myString, "some")
    disp Yes
else
    disp No
end

Yes

[Pat Canny]

Yep, I also tried that. It works fine for two substrings, but what if there are several?

Answer 4

[Steven Lord]

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.

[Stephen23]

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]

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

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