Which Python function is used to cast a value to an integer?

The function used to cast a value to an integer in Python is int(). This function takes an argument, which can be a number, a string representing a number, or a floating-point number, and converts it to an integer type.

When you pass a float to the int() function, it truncates the decimal portion and returns just the whole number. For example, int(3.9) would result in 3. If you pass a string like '42', int('42') will successfully convert it to the integer 42. If the string is not a valid representation of an integer (like 'abc'), this will raise a ValueError.

The other functions presented do not serve this casting purpose. The float() function converts a value to a floating-point number, the str() function converts a value to a string, and the char() function is not a built-in function in Python. Thus, the proper choice for converting a value to an integer is indeed int().