I know the contains method tests to see if a string contains at least one of the letters you entered, but how do I set it to test if there's one at the most?
thekidj wrote ...
2013/10/17
Contains one occurrence?
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You can't set the method to have an alternative behavior when it has no support for such. You will have to implement something. Looks like you could use the indexOf and lastIndexOf methods to get what you want. Something like:
String myString;
...
int firstIndex = myString.indexOf( something );
int lastIndex = myString.lastIndexOf( something );
if (firstIndex != -1 && firstIndex == lastIndex)
{
// Only one occurrence of something in myString. Where something is another String or just a char
}bourne wrote...
You can't set the method to have an alternative behavior when it has no support for such. You will have to implement something. Looks like you could use the indexOf and lastIndexOf methods to get what you want. Something like:
String myString;
...
int firstIndex = myString.indexOf( something );
int lastIndex = myString.lastIndexOf( something );
if (firstIndex != -1 && firstIndex == lastIndex)
{
// Only one occurrence of something in myString. Where something is another String or just a char
}/**
* Constructor for objects of class FriendList
*/
public FriendList()
{
friend = new ArrayList<Person>();
}
public void add(Person p)
{
friend.add(p);
}
public Person get(int index)
{
if (index >= 0 && index < friend.size())
{
return friend.get(index);
}
else
{
return null;
}
}
public boolean purge(int index)
{
if (index >= 0 && index < friend.size())
{
friend.remove(index);
return true;
}
else
{
return false;
}
}
public void putLast(int index)
{
if (index >= 0 && index < friend.size())
{
Person end = friend.remove(index);
friend.add(end);
}
}
public void list()
{
int index = 0;
while(index < friend.size())
{
Person x = friend.get(index);
System.out.println("Friend's Name: " + x.getName());
System.out.println("Friend's Number: D00" + x.getMemberNumber());
System.out.println();
index++;
}
}
public void listContainingAtLeastOne(String str)
{
int index = 0;
while(index <friend.size())
{
Person x = friend.get(index);
if (x.getName().contains(str))
{
System.out.println(x.getName());
}
index++;
}
}
public void listContainingAtMostOne(String str)
{
}
}
In your method listContainingAtMostOne(String str), do what you did in the method above it, but change the if statement to mine. While exchanging "something" with "str", and exchanging "myString" with "x.getName()".
If you want it to include those that do not contain (i.e. contains one or none) then change
if (firstIndex != -1 && firstIndex == lastIndex)
to
if (firstIndex == -1 || firstIndex == lastIndex)
bourne wrote...
In your method listContainingAtMostOne(String str), do what you did in the method above it, but change the if statement to mine. While exchanging "something" with "str", and exchanging "myString" with "x.getName()".What number? And exactly one character of what?
I believe you are under the impression that the contains method returns true if at least one char of the input is within the String.
This is not the case.
The contains method "Returns true if and only if this string contains the specified sequence of char values."
"apple".contains("aple") // returns false
"apple".contains("ee") // returns false
"apple".contains("Apple") // returns false
"apple".contains("apple") // returns true
"apple".contains("pp") // returns true
"apple".contains("e") // returns true
bourne wrote...
What number? And exactly one character of what?
I believe you are under the impression that the contains method returns true if at least one char of the input is within the String.
This is not the case.
The contains method "Returns true if and only if this string contains the specified sequence of char values."
"apple".contains("aple") // returns false
"apple".contains("ee") // returns false
"apple".contains("Apple") // returns false
"apple".contains("apple") // returns true
"apple".contains("pp") // returns true
"apple".contains("e") // returns trueMy original if statement,
if (firstIndex != -1 && firstIndex == lastIndex)
gets its block of code executed if it is contained, and only once
bourne wrote...
My original if statement,
if (firstIndex != -1 && firstIndex == lastIndex)
gets its block of code executed if it is contained, and only once int index = 0;
while(index < friend.size())
{
Person x = friend.get(index);
int firstIndex = x.getName().indexOf(str);
int lastIndex = x.getName().lastIndexOf(str);
if (firstIndex != -1 && firstIndex == lastIndex)
{
friend.remove(x.getName());
}
index++;
}
You probably wanted to use 'friend.remove(index)'.
However, you should also, subtract one from the index immediately afterwards within the same 'if' block, so you do not skip over the next element in the list (which will now occupy the same index that you removed your last friend from).
Give me an example data (name of a Person) and an str that you would expect it to be removed
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