python - How to Check list containing NaN

Python - How to Check list containing NaN

To check if a list contains NaN (Not a Number) values in Python, you can use the math.isnan function along with a loop or list comprehension. Here's an example:

import math def has_nan(input_list): return any(math.isnan(x) for x in input_list) # Example usage my_list = [1.0, 2.0, float('nan'), 4.0, 5.0] if has_nan(my_list): print("The list contains NaN.") else: print("The list does not contain NaN.") 

In this example:

  • The has_nan function checks if any element in the input list is NaN using math.isnan.
  • The any function returns True if at least one element is NaN.

Note: The math.isnan function works with float values. If you're working with lists containing non-float types or need to handle NaN values in other types, additional checks may be required.

If you're using NumPy, you can also use the numpy.isnan function:

import numpy as np def has_nan(input_list): return any(np.isnan(x) for x in input_list) # Example usage my_list = [1.0, 2.0, np.nan, 4.0, 5.0] if has_nan(my_list): print("The list contains NaN.") else: print("The list does not contain NaN.") 

This approach is more flexible and can handle NaN values in NumPy arrays as well.

Examples

  1. "Python check if a list contains NaN using math.isnan"

    • Code Implementation:
      import math def has_nan_using_math_isnan(lst): return any(math.isnan(value) for value in lst) # Example usage my_list = [1.0, 2.5, float('nan'), 4.8] result = has_nan_using_math_isnan(my_list) print(result) 
    • Description: Uses math.isnan to check if any element in the list is NaN.
  2. "Python check if a list has NaN using numpy"

    • Code Implementation:
      import numpy as np def has_nan_using_numpy(lst): return np.isnan(lst).any() # Example usage my_list = [2.0, 3.7, np.nan, 5.1] result = has_nan_using_numpy(my_list) print(result) 
    • Description: Utilizes NumPy to check if any element in the list is NaN.
  3. "Python check if a list contains NaN using math.isnan with filter"

    • Code Implementation:
      import math def has_nan_using_math_isnan_filter(lst): return any(filter(math.isnan, lst)) # Example usage my_list = [1.2, 3.0, 2.5, float('nan')] result = has_nan_using_math_isnan_filter(my_list) print(result) 
    • Description: Applies math.isnan with filter to check if any element in the list is NaN.
  4. "Python check if a list has NaN using any and isnan"

    • Code Implementation:
      import math def has_nan_using_any_and_isnan(lst): return any(math.isnan(value) for value in lst) # Example usage my_list = [4.2, 2.3, float('nan'), 6.7] result = has_nan_using_any_and_isnan(my_list) print(result) 
    • Description: Uses any with isnan to check if any element in the list is NaN.
  5. "Python check if a list contains NaN using pandas"

    • Code Implementation:
      import pandas as pd def has_nan_using_pandas(lst): return pd.Series(lst).isna().any() # Example usage my_list = [2.3, 5.6, float('nan'), 8.1] result = has_nan_using_pandas(my_list) print(result) 
    • Description: Converts the list to a Pandas Series and uses isna to check if any element is NaN.
  6. "Python check if a list has NaN using list comprehension"

    • Code Implementation:
      def has_nan_using_list_comprehension(lst): return any(math.isnan(value) for value in lst) # Example usage my_list = [3.4, 1.8, float('nan'), 7.2] result = has_nan_using_list_comprehension(my_list) print(result) 
    • Description: Employs a list comprehension to check if any element in the list is NaN.
  7. "Python check if a list contains NaN using set and isnan"

    • Code Implementation:
      import math def has_nan_using_set_and_isnan(lst): return math.isnan(next(iter(set(lst).intersection({float('nan')})), None)) # Example usage my_list = [2.6, 4.0, float('nan'), 6.3] result = has_nan_using_set_and_isnan(my_list) print(result) 
    • Description: Uses set and isnan to check if any element in the list is NaN.
  8. "Python check if a list has NaN using isnan and all"

    • Code Implementation:
      import math def has_nan_using_isnan_and_all(lst): return all(not math.isnan(value) for value in lst) # Example usage my_list = [1.5, 3.9, 2.2, 6.4] result = has_nan_using_isnan_and_all(my_list) print(result) 
    • Description: Uses isnan with all to check if all elements in the list are not NaN.
  9. "Python check if a list contains NaN using lambda function"

    • Code Implementation:
      has_nan = lambda lst: any(math.isnan(value) for value in lst) # Example usage my_list = [2.8, 4.6, float('nan'), 7.1] result = has_nan(my_list) print(result) 
    • Description: Defines a lambda function to check if any element in the list is NaN.
  10. "Python check if a list has NaN using map and isnan"

    • Code Implementation:
      import math def has_nan_using_map(lst): return any(map(lambda value: math.isnan(value), lst)) # Example usage my_list = [3.1, 5.8, float('nan'), 9.2] result = has_nan_using_map(my_list) print(result) 
    • Description: Applies map with isnan to check if any element in the list is NaN.

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