Opposite of .contains (does not contain)

Question

I have an if statement:

if (inventory.contains("bread"))

But now I want to check

if inventory contains "bread"
but does not contain "water".

How can I do this?

`if(inventory.contains("bread") && !inventory.contains("water"))`? — Luiggi Mendoza, Mar 31 '13 at 13:57
Don't see why nobody mentioned that contains() returns a boolean so true if it contains the value or false if it doesn't. — Drew, Mar 31 '13 at 14:51
I didn't say OP did, but if you have to ask how to check a boolean it would be helpful to note because op probably know what !boolean means. — Drew, Mar 31 '13 at 18:00

score 72 · Accepted Answer · edited Nov 28 '20 at 02:47

72

It seems that Luiggi Mendoza and joey rohan both already answered this, but I think it can be clarified a little.

You can write it as a single if statement:

if (inventory.contains("bread") && !inventory.contains("water")) {
    // do something
}

edited Nov 28 '20 at 02:47

informatik01

16,038
10
74
104

answered Jul 10 '13 at 17:10

Itsan Alias

840
8
8

As per clean code principle ! should be avoided in conditions. Ideal would be to extract !inventory.contains( ingredient ) should be extracted to a separate method e.g. boolean inventoryDoesNotHave(ingredient) – antnewbee Jun 22 '23 at 07:55

score 6 · Answer 2 · edited Nov 28 '20 at 02:48

6

Maybe

if (inventory.contains("bread") && !inventory.contains("water"))

Or

if (inventory.contains("bread")) {
    if (!inventory.contains("water")) {
        // do something here
    } 
}

edited Nov 28 '20 at 02:48

informatik01

16,038
10
74
104

answered Mar 31 '13 at 14:02

joey rohan

3,505
5
33
70

I think you meant `if(!inventory.contains("water"))` for the second test. – Patricia Shanahan Mar 31 '13 at 14:16
You still have unbalanced parentheses. – Patricia Shanahan Mar 31 '13 at 19:10
@PatriciaShanahan for me it looks ok..won't you mind editing the answer? – joey rohan Apr 01 '13 at 03:56

Ashish Gupta · Answer 3 · 2021-05-27T10:41:22.993

For your questions, use below

if(inventory.contains("bread") && !inventory.contains("water")) {

System.out.println("Bread is there and water not there");

}

else{

System.out.println("Both or any one condition not met");

}

Another example: Just use ! sign before contains function.

like if you want to perform some action, like if list does contains say stack then add stack.

   if (!list.contains("stack")) {
        list.add("stack");
    }`

or another method, if index of search string is -1,

 if(list.indexOf("stack")==-1){
    list.add("stack");

}

score 0 · Answer 4 · answered Apr 04 '22 at 10:04

0

I know we can use the '!' to get the opposite value of the String.contains() function. If you do not want to use the '!' symbol, use the following code:

if(inventory.contains("bread"))
{
    if(inventory.contains("water"))
    {
        //do nothing
    }
    else
    {
        //do what you intend to do
    }
}

answered Apr 04 '22 at 10:04

Sardaar54

1
3

it is Ok but it is not a cleaner code than the second answer – Nwawel A Iroume Apr 05 '22 at 13:42
Second answer also has "!" in the second if statement. – Sardaar54 Apr 06 '22 at 09:24

Opposite of .contains (does not contain)

4 Answers4