金声玉亮2.0模型评测报告

Complete the following python code:

def count_distinct_characters(string: str) -> int:
""" Given a string, find out how many distinct characters (regardless of case) does it consist of
>>> count_distinct_characters('xyzXYZ')
3
>>> count_distinct_characters('Jerry')
4
"""

答案

模型	模型答案	测试结果
金声玉亮2.0	Certainly! Below is the completed Python code for the `count_distinct_characters` function: ```python def count_distinct_characters(string: str) -> int: """ Given a string, find out how many distinct characters (regardless of case) does it consist of >>> count_distinct_characters('xyzXYZ') 3 >>> count_distinct_characters('Jerry') 4 """ # Convert the string to lowercase to ignore case differences string = string.lower() # Use a set to keep track of distinct characters distinct_characters = set(string) # Return the number of distinct characters return len(distinct_characters) # Test cases if __name__ == "__main__": import doctest doctest.testmod() ``` This function works by first converting the input string to lowercase to ensure that the case of the characters is ignored. It then creates a set from the string, which automatically handles duplicate characters. Finally, it returns the length of the set, which represents the number of distinct characters in the string.	passed
deepseekr1	To solve this problem, we need to determine the number of distinct characters in a given string, regardless of their case. This means that characters 'A' and 'a' should be considered the same. ### Approach The approach to solve this problem involves the following steps: 1. Convert to Lowercase: Convert all characters in the input string to lowercase to ensure case insensitivity. This means 'A' becomes 'a', 'B' becomes 'b', and so on. 2. Create a Set of Characters: Use a set to store the characters from the converted lowercase string. A set automatically handles uniqueness, so each character will appear only once in the set. 3. Count Unique Characters: The length of the set created in the previous step will give the number of distinct characters in the original string, considering case insensitivity. This approach efficiently handles the problem by leveraging the properties of sets to ensure uniqueness and the string method to handle case conversion. ### Solution Code ```python def count_distinct_characters(string: str) -> int: return len(set(string.lower())) ``` ### Explanation 1. Convert to Lowercase: The method `string.lower()` is used to convert all characters in the input string to lowercase. This ensures that characters differing only in case are treated as the same character. 2. Create a Set: By converting the string to a set, `set(string.lower())`, we automatically remove any duplicate characters, leaving only unique characters. 3. Count Unique Characters: The `len()` function is then used to determine the number of elements in the set, which corresponds to the number of distinct characters in the original string, considering case insensitivity. This solution is efficient with a time complexity of O(n), where n is the length of the string, as converting to lowercase and creating a set both operate in linear time. The space complexity is also O(n) in the worst case where all characters are unique.	passed
gpto1	To count the number of distinct characters regardless of case, you can convert the string to all lower (or upper) case, then use a set to keep only unique characters, and finally return the length of that set. Here's the complete function: ```python def count_distinct_characters(string: str) -> int: """ Given a string, find out how many distinct characters (regardless of case) does it consist of >>> count_distinct_characters('xyzXYZ') 3 >>> count_distinct_characters('Jerry') 4 """ return len(set(string.lower())) ```	passed
GPT-4o	Certainly! To complete the function `count_distinct_characters`, we can use Python's set data structure which inherently stores only unique elements. Here's the completed code: ```python def count_distinct_characters(string: str) -> int: """ Given a string, find out how many distinct characters (regardless of case) does it consist of >>> count_distinct_characters('xyzXYZ') 3 >>> count_distinct_characters('Jerry') 4 """ # Convert the string to lowercase to ignore case differences string = string.lower() # Use a set to store distinct characters distinct_characters = set(string) # Return the number of distinct characters return len(distinct_characters) # Example usage if __name__ == "__main__": import doctest doctest.testmod() ``` This function converts the input string to lowercase to ensure that the character count is case-insensitive. It then creates a set from the string, which automatically removes any duplicate characters. Finally, it returns the size of the set, which corresponds to the number of distinct characters in the input string. The examples provided in the docstring will pass the test cases when run.	passed
llama3.1-70B-Instruct	def count_distinct_characters(string: str) -> int: """ Given a string, find out how many distinct characters (regardless of case) does it consist of >>> count_distinct_characters('xyzXYZ') 3 >>> count_distinct_characters('Jerry') 4 """ return len(set(string.casefold()))	passed
llama3.1-405B-Instruct	def count_distinct_characters(string: str) -> int: """ Given a string, find out how many distinct characters (regardless of case) does it consist of >>> count_distinct_characters('xyzXYZ') 3 >>> count_distinct_characters('Jerry') 4 """ # Convert the string to lowercase to ignore case string = string.lower() # Convert the string to a set, which automatically removes duplicates distinct_chars = set(string) # Return the number of distinct characters return len(distinct_chars)	passed
DeepSeek-Coder-V2	Here's the completed Python function that counts the number of distinct characters in a given string, regardless of their case: ```python def count_distinct_characters(string: str) -> int: """ Given a string, find out how many distinct characters (regardless of case) does it consist of >>> count_distinct_characters('xyzXYZ') 3 >>> count_distinct_characters('Jerry') 4 """ # Convert the string to lowercase to ignore case lower_string = string.lower() # Use a set to store distinct characters distinct_characters = set(lower_string) # Return the number of distinct characters return len(distinct_characters) # Test cases if __name__ == "__main__": import doctest doctest.testmod() ``` This function first converts the input string to lowercase to ensure that the character comparison is case-insensitive. Then, it uses a set to store the distinct characters, as sets automatically remove duplicates. Finally, it returns the length of the set, which represents the number of distinct characters in the string. The test cases provided in the docstring are also included to verify the function's correctness.	passed
Qwen2-72B-Instruct	```python def count_distinct_characters(string: str) -> int: return len(set(string.lower())) print(count_distinct_characters('xyzXYZ')) # Output: 3 print(count_distinct_characters('Jerry')) # Output: 4 ``` Note that I used `set(string.lower())` to convert the string to lowercase and then to a set, which automatically removes any duplicate characters. The length of this set is then returned as the number of distinct characters in the string.	passed
baichuan4	To complete the Python code for the `count_distinct_characters` function, we need to convert the input string to lowercase and then use a set to keep track of distinct characters. Here's the completed function: ```python def count_distinct_characters(string: str) -> int: """ Given a string, find out how many distinct characters (regardless of case) does it consist of >>> count_distinct_characters('xyzXYZ') 3 >>> count_distinct_characters('Jerry') 4 """ # Convert the string to lowercase to ensure case insensitivity lowercase_string = string.lower() # Use a set to store distinct characters distinct_chars = set() # Iterate over each character in the string for char in lowercase_string: # Add the character to the set (sets automatically ensure uniqueness) distinct_chars.add(char) # The number of distinct characters is the size of the set return len(distinct_chars) # Example usage: print(count_distinct_characters('xyzXYZ')) # Output: 3 print(count_distinct_characters('Jerry')) # Output: 4 ``` This function works by first converting the entire input string to lowercase, which ensures that uppercase and lowercase versions of the same letter are treated as identical. Then, it iterates through each character of the lowercase string, adding each character to a set. Since sets automatically eliminate duplicates, only distinct characters will remain in the set. Finally, the function returns the number of elements in the set, which corresponds to the count of distinct characters in the input string.	passed
doubao	Here's the completed Python code: ```python def count_distinct_characters(string: str) -> int: return len(set(string.lower())) # Test cases print(count_distinct_characters('xyzXYZ')) print(count_distinct_characters('Jerry')) ```	passed
minimax	To complete the function `count_distinct_characters`, we need to count the number of unique characters in the input string, ignoring the case. We can achieve this by converting the string to lowercase (or uppercase) and then using a data structure like a set to keep track of the distinct characters. Here's the completed function: ```python def count_distinct_characters(string: str) -> int: """ Given a string, find out how many distinct characters (regardless of case) does it consist of >>> count_distinct_characters('xyzXYZ') 3 >>> count_distinct_characters('Jerry') 4 """ # Convert the string to lowercase to ignore case lower_string = string.lower() # Use a set to store unique characters unique_chars = set(lower_string) # The number of unique characters is the size of the set return len(unique_chars) # Example usage: print(count_distinct_characters('xyzXYZ')) # Output: 3 print(count_distinct_characters('Jerry')) # Output: 4 ``` The `set` data structure in Python automatically ensures that only unique elements are stored, so when we add all characters of the string to the set, we end up with a set of unique characters. The `len` function then returns the number of elements in the set, which is the number of distinct characters in the string.	passed
kimi	Here's the completed Python code for the function `count_distinct_characters`: ```python def count_distinct_characters(string: str) -> int: """ Given a string, find out how many distinct characters (regardless of case) does it consist of >>> count_distinct_characters('xyzXYZ') 3 >>> count_distinct_characters('Jerry') 4 """ # Convert the string to lowercase to make the count case-insensitive string = string.lower() # Use a set to store unique characters unique_characters = set(string) # Return the number of unique characters return len(unique_characters) # Test cases print(count_distinct_characters('xyzXYZ')) # Should print 3 print(count_distinct_characters('Jerry')) # Should print 4 ``` This function converts the input string to lowercase to ensure that the character count is case-insensitive. It then uses a set to store unique characters, as sets automatically discard duplicates. Finally, it returns the length of the set, which corresponds to the number of distinct characters in the string.	passed
wenxinyiyan	To count the number of distinct characters in a string, regardless of case, you can use a set. Here's the completed code for the `count_distinct_characters` function: ```python def count_distinct_characters(string: str) -> int: """ Given a string, find out how many distinct characters (regardless of case) does it consist of >>> count_distinct_characters('xyzXYZ') 3 >>> count_distinct_characters('Jerry') 4 """ # Convert the string to lowercase to ignore case sensitivity lowercase_string = string.lower() # Use a set to store distinct characters distinct_chars = set(lowercase_string) # Return the count of distinct characters return len(distinct_chars) ``` In this code, we first convert the input string to lowercase using the `lower()` method. This ensures that case sensitivity is ignored when counting distinct characters. Then, we create a set called `distinct_chars` by passing the lowercase string to the `set()` function. A set is a collection of unique elements, so it automatically removes any duplicates. Finally, we return the length of the `distinct_chars` set, which gives us the count of distinct characters in the input string.	passed
zhipu	Certainly! To complete the function `count_distinct_characters`, you can use a set to store unique characters after converting the string to a uniform case (either all lowercase or all uppercase). This approach ensures that characters are counted regardless of their case. Here's the complete code: ```python def count_distinct_characters(string: str) -> int: """ Given a string, find out how many distinct characters (regardless of case) does it consist of >>> count_distinct_characters('xyzXYZ') 3 >>> count_distinct_characters('Jerry') 4 """ # Convert the string to lowercase to make the function case-insensitive string = string.lower() # Use a set to store unique characters distinct_characters = set(string) # Return the number of distinct characters return len(distinct_characters) # Example usage: if __name__ == "__main__": import doctest doctest.testmod() ``` ### Explanation: 1. Convert to Lowercase: `string.lower()` converts the entire string to lowercase, ensuring that 'A' and 'a' are treated as the same character. 2. Use a Set: A set automatically handles uniqueness, so adding all characters of the string to a set will filter out duplicates. 3. Return the Length: The length of the set gives the count of distinct characters. ### Running the Doctests: The `if __name__ == "__main__":` block allows you to run the doctests when the script is executed directly. The `doctest.testmod()` function will check the examples provided in the docstring to ensure the function behaves as expected. You can run this script directly, and it will verify the examples given in the docstrings. If you want to test it manually, you can simply call the function with different strings: ```python print(count_distinct_characters('xyzXYZ')) # Output: 3 print(count_distinct_characters('Jerry')) # Output: 4 ```	passed
gpto1	To count the number of distinct characters regardless of case, you can convert the string to all lower (or upper) case, then use a set to keep only unique characters, and finally return the length of that set. Here's the complete function: ```python def count_distinct_characters(string: str) -> int: """ Given a string, find out how many distinct characters (regardless of case) does it consist of >>> count_distinct_characters('xyzXYZ') 3 >>> count_distinct_characters('Jerry') 4 """ return len(set(string.lower())) ```	passed
deepseekv3	To complete the `count_distinct_characters` function, we need to count the number of distinct characters in the given string, regardless of their case. Here's how you can implement it: ```python def count_distinct_characters(string: str) -> int: """ Given a string, find out how many distinct characters (regardless of case) does it consist of >>> count_distinct_characters('xyzXYZ') 3 >>> count_distinct_characters('Jerry') 4 """ # Convert the string to lowercase to make the comparison case-insensitive lowercase_string = string.lower() # Use a set to store unique characters distinct_characters = set(lowercase_string) # Return the number of unique characters return len(distinct_characters) # Test cases if __name__ == "__main__": import doctest doctest.testmod() ``` ### Explanation: 1. Convert to Lowercase: The string is converted to lowercase using `string.lower()`. This ensures that characters like 'A' and 'a' are treated as the same. 2. Use a Set: A set is used to store the characters because sets automatically handle uniqueness. Only distinct characters will be added to the set. 3. Count Distinct Characters: The length of the set, which represents the number of distinct characters, is returned. ### Example Output: - For the input `'xyzXYZ'`, the function will return `3` because the distinct characters are 'x', 'y', and 'z'. - For the input `'Jerry'`, the function will return `4` because the distinct characters are 'j', 'e', 'r', and 'y'. This function is case-insensitive and correctly counts the number of distinct characters in the string.	passed

模型

模型答案

测试结果

金声玉亮2.0

Certainly! Below is the completed Python code for the `count_distinct_characters` function:

```python
def count_distinct_characters(string: str) -> int:
""" Given a string, find out how many distinct characters (regardless of case) does it consist of
>>> count_distinct_characters('xyzXYZ')
3
>>> count_distinct_characters('Jerry')
4
"""
# Convert the string to lowercase to ignore case differences
string = string.lower()
# Use a set to keep track of distinct characters
distinct_characters = set(string)
# Return the number of distinct characters
return len(distinct_characters)

# Test cases
if __name__ == "__main__":
import doctest
doctest.testmod()
```

This function works by first converting the input string to lowercase to ensure that the case of the characters is ignored. It then creates a set from the string, which automatically handles duplicate characters. Finally, it returns the length of the set, which represents the number of distinct characters in the string.

passed

deepseekr1

To solve this problem, we need to determine the number of distinct characters in a given string, regardless of their case. This means that characters 'A' and 'a' should be considered the same.

### Approach
The approach to solve this problem involves the following steps:
1. **Convert to Lowercase**: Convert all characters in the input string to lowercase to ensure case insensitivity. This means 'A' becomes 'a', 'B' becomes 'b', and so on.
2. **Create a Set of Characters**: Use a set to store the characters from the converted lowercase string. A set automatically handles uniqueness, so each character will appear only once in the set.
3. **Count Unique Characters**: The length of the set created in the previous step will give the number of distinct characters in the original string, considering case insensitivity.

This approach efficiently handles the problem by leveraging the properties of sets to ensure uniqueness and the string method to handle case conversion.

### Solution Code

```python
def count_distinct_characters(string: str) -> int:
return len(set(string.lower()))
```

### Explanation
1. **Convert to Lowercase**: The method `string.lower()` is used to convert all characters in the input string to lowercase. This ensures that characters differing only in case are treated as the same character.
2. **Create a Set**: By converting the string to a set, `set(string.lower())`, we automatically remove any duplicate characters, leaving only unique characters.
3. **Count Unique Characters**: The `len()` function is then used to determine the number of elements in the set, which corresponds to the number of distinct characters in the original string, considering case insensitivity.

This solution is efficient with a time complexity of O(n), where n is the length of the string, as converting to lowercase and creating a set both operate in linear time. The space complexity is also O(n) in the worst case where all characters are unique.

passed

gpto1

To count the number of distinct characters regardless of case, you can convert the string to all lower (or upper) case, then use a set to keep only unique characters, and finally return the length of that set.

Here's the complete function:

```python
def count_distinct_characters(string: str) -> int:
""" Given a string, find out how many distinct characters (regardless of case) does it consist of
>>> count_distinct_characters('xyzXYZ')
3
>>> count_distinct_characters('Jerry')
4
"""
return len(set(string.lower()))
```

passed

GPT-4o

Certainly! To complete the function `count_distinct_characters`, we can use Python's set data structure which inherently stores only unique elements. Here's the completed code:

```python
def count_distinct_characters(string: str) -> int:
""" Given a string, find out how many distinct characters (regardless of case) does it consist of
>>> count_distinct_characters('xyzXYZ')
3
>>> count_distinct_characters('Jerry')
4
"""
# Convert the string to lowercase to ignore case differences
string = string.lower()

# Use a set to store distinct characters
distinct_characters = set(string)

# Return the number of distinct characters
return len(distinct_characters)

# Example usage
if __name__ == "__main__":
import doctest
doctest.testmod()
```

This function converts the input string to lowercase to ensure that the character count is case-insensitive. It then creates a set from the string, which automatically removes any duplicate characters. Finally, it returns the size of the set, which corresponds to the number of distinct characters in the input string. The examples provided in the docstring will pass the test cases when run.

passed

llama3.1-70B-Instruct

passed

llama3.1-405B-Instruct

def count_distinct_characters(string: str) -> int:
""" Given a string, find out how many distinct characters (regardless of case) does it consist of
>>> count_distinct_characters('xyzXYZ')
3
>>> count_distinct_characters('Jerry')
4
"""
# Convert the string to lowercase to ignore case
string = string.lower()

# Convert the string to a set, which automatically removes duplicates
distinct_chars = set(string)

# Return the number of distinct characters
return len(distinct_chars)

passed

DeepSeek-Coder-V2

Here's the completed Python function that counts the number of distinct characters in a given string, regardless of their case:

```python
def count_distinct_characters(string: str) -> int:
""" Given a string, find out how many distinct characters (regardless of case) does it consist of
>>> count_distinct_characters('xyzXYZ')
3
>>> count_distinct_characters('Jerry')
4
"""
# Convert the string to lowercase to ignore case
lower_string = string.lower()
# Use a set to store distinct characters
distinct_characters = set(lower_string)
# Return the number of distinct characters
return len(distinct_characters)

# Test cases
if __name__ == "__main__":
import doctest
doctest.testmod()
```

This function first converts the input string to lowercase to ensure that the character comparison is case-insensitive. Then, it uses a set to store the distinct characters, as sets automatically remove duplicates. Finally, it returns the length of the set, which represents the number of distinct characters in the string. The test cases provided in the docstring are also included to verify the function's correctness.

passed

Qwen2-72B-Instruct

```python
def count_distinct_characters(string: str) -> int:
return len(set(string.lower()))

print(count_distinct_characters('xyzXYZ')) # Output: 3
print(count_distinct_characters('Jerry')) # Output: 4
```

Note that I used `set(string.lower())` to convert the string to lowercase and then to a set, which automatically removes any duplicate characters. The length of this set is then returned as the number of distinct characters in the string.

passed

baichuan4

To complete the Python code for the `count_distinct_characters` function, we need to convert the input string to lowercase and then use a set to keep track of distinct characters. Here's the completed function:

```python
def count_distinct_characters(string: str) -> int:
""" Given a string, find out how many distinct characters (regardless of case) does it consist of
>>> count_distinct_characters('xyzXYZ')
3
>>> count_distinct_characters('Jerry')
4
"""
# Convert the string to lowercase to ensure case insensitivity
lowercase_string = string.lower()

# Use a set to store distinct characters
distinct_chars = set()

# Iterate over each character in the string
for char in lowercase_string:
# Add the character to the set (sets automatically ensure uniqueness)
distinct_chars.add(char)

# The number of distinct characters is the size of the set
return len(distinct_chars)

# Example usage:
print(count_distinct_characters('xyzXYZ')) # Output: 3
print(count_distinct_characters('Jerry')) # Output: 4
```

This function works by first converting the entire input string to lowercase, which ensures that uppercase and lowercase versions of the same letter are treated as identical. Then, it iterates through each character of the lowercase string, adding each character to a set. Since sets automatically eliminate duplicates, only distinct characters will remain in the set. Finally, the function returns the number of elements in the set, which corresponds to the count of distinct characters in the input string.

passed

doubao

Here's the completed Python code:

```python
def count_distinct_characters(string: str) -> int:
return len(set(string.lower()))

# Test cases
print(count_distinct_characters('xyzXYZ'))
print(count_distinct_characters('Jerry'))
```

passed

minimax

To complete the function `count_distinct_characters`, we need to count the number of unique characters in the input string, ignoring the case. We can achieve this by converting the string to lowercase (or uppercase) and then using a data structure like a set to keep track of the distinct characters. Here's the completed function:

```python
def count_distinct_characters(string: str) -> int:
""" Given a string, find out how many distinct characters (regardless of case) does it consist of
>>> count_distinct_characters('xyzXYZ')
3
>>> count_distinct_characters('Jerry')
4
"""
# Convert the string to lowercase to ignore case
lower_string = string.lower()

# Use a set to store unique characters
unique_chars = set(lower_string)

# The number of unique characters is the size of the set
return len(unique_chars)

# Example usage:
print(count_distinct_characters('xyzXYZ')) # Output: 3
print(count_distinct_characters('Jerry')) # Output: 4
```

The `set` data structure in Python automatically ensures that only unique elements are stored, so when we add all characters of the string to the set, we end up with a set of unique characters. The `len` function then returns the number of elements in the set, which is the number of distinct characters in the string.

passed

kimi

Here's the completed Python code for the function `count_distinct_characters`:

```python
def count_distinct_characters(string: str) -> int:
""" Given a string, find out how many distinct characters (regardless of case) does it consist of
>>> count_distinct_characters('xyzXYZ')
3
>>> count_distinct_characters('Jerry')
4
"""
# Convert the string to lowercase to make the count case-insensitive
string = string.lower()
# Use a set to store unique characters
unique_characters = set(string)
# Return the number of unique characters
return len(unique_characters)

# Test cases
print(count_distinct_characters('xyzXYZ')) # Should print 3
print(count_distinct_characters('Jerry')) # Should print 4
```

This function converts the input string to lowercase to ensure that the character count is case-insensitive. It then uses a set to store unique characters, as sets automatically discard duplicates. Finally, it returns the length of the set, which corresponds to the number of distinct characters in the string.

passed

wenxinyiyan

To count the number of distinct characters in a string, regardless of case, you can use a set. Here's the completed code for the `count_distinct_characters` function:

```python
def count_distinct_characters(string: str) -> int:
""" Given a string, find out how many distinct characters (regardless of case) does it consist of
>>> count_distinct_characters('xyzXYZ')
3
>>> count_distinct_characters('Jerry')
4
"""
# Convert the string to lowercase to ignore case sensitivity
lowercase_string = string.lower()

# Use a set to store distinct characters
distinct_chars = set(lowercase_string)

# Return the count of distinct characters
return len(distinct_chars)
```
In this code, we first convert the input string to lowercase using the `lower()` method. This ensures that case sensitivity is ignored when counting distinct characters.

Then, we create a set called `distinct_chars` by passing the lowercase string to the `set()` function. A set is a collection of unique elements, so it automatically removes any duplicates.

Finally, we return the length of the `distinct_chars` set, which gives us the count of distinct characters in the input string.

passed

zhipu

Certainly! To complete the function `count_distinct_characters`, you can use a set to store unique characters after converting the string to a uniform case (either all lowercase or all uppercase). This approach ensures that characters are counted regardless of their case. Here's the complete code:

```python
def count_distinct_characters(string: str) -> int:
""" Given a string, find out how many distinct characters (regardless of case) does it consist of
>>> count_distinct_characters('xyzXYZ')
3
>>> count_distinct_characters('Jerry')
4
"""
# Convert the string to lowercase to make the function case-insensitive
string = string.lower()

# Use a set to store unique characters
distinct_characters = set(string)

# Return the number of distinct characters
return len(distinct_characters)

# Example usage:
if __name__ == "__main__":
import doctest
doctest.testmod()
```

### Explanation:
1. **Convert to Lowercase**: `string.lower()` converts the entire string to lowercase, ensuring that 'A' and 'a' are treated as the same character.
2. **Use a Set**: A set automatically handles uniqueness, so adding all characters of the string to a set will filter out duplicates.
3. **Return the Length**: The length of the set gives the count of distinct characters.

### Running the Doctests:
The `if __name__ == "__main__":` block allows you to run the doctests when the script is executed directly. The `doctest.testmod()` function will check the examples provided in the docstring to ensure the function behaves as expected.

You can run this script directly, and it will verify the examples given in the docstrings. If you want to test it manually, you can simply call the function with different strings:

```python
print(count_distinct_characters('xyzXYZ')) # Output: 3
print(count_distinct_characters('Jerry')) # Output: 4
```

passed

gpto1

passed

deepseekv3

To complete the `count_distinct_characters` function, we need to count the number of distinct characters in the given string, regardless of their case. Here's how you can implement it:

```python
def count_distinct_characters(string: str) -> int:
""" Given a string, find out how many distinct characters (regardless of case) does it consist of
>>> count_distinct_characters('xyzXYZ')
3
>>> count_distinct_characters('Jerry')
4
"""
# Convert the string to lowercase to make the comparison case-insensitive
lowercase_string = string.lower()

# Use a set to store unique characters
distinct_characters = set(lowercase_string)

# Return the number of unique characters
return len(distinct_characters)

# Test cases
if __name__ == "__main__":
import doctest
doctest.testmod()
```

### Explanation:
1. **Convert to Lowercase**: The string is converted to lowercase using `string.lower()`. This ensures that characters like 'A' and 'a' are treated as the same.
2. **Use a Set**: A set is used to store the characters because sets automatically handle uniqueness. Only distinct characters will be added to the set.
3. **Count Distinct Characters**: The length of the set, which represents the number of distinct characters, is returned.

### Example Output:
- For the input `'xyzXYZ'`, the function will return `3` because the distinct characters are 'x', 'y', and 'z'.
- For the input `'Jerry'`, the function will return `4` because the distinct characters are 'j', 'e', 'r', and 'y'.

This function is case-insensitive and correctly counts the number of distinct characters in the string.

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