Check If a Number Is an Integer in Python
This article explains how to check if a number is an integer or has a fractional part in Python.
See the following article to learn how to obtain the fractional and integer parts of a number.
See the following article to check if a string is a number.
Check if an object is int or float: isinstance()
You can get the type of an object using the built-in type() function.
i = 100 f = 1.23 print(type(i)) print(type(f)) # <class 'int'> # <class 'float'> You can also check if an object is of a specific type using the built-in isinstance() function.
print(isinstance(i, int)) # True print(isinstance(i, float)) # False print(isinstance(f, int)) # False print(isinstance(f, float)) # True Since this approach only checks the type, it cannot determine whether a float value represents an integer (i.e., whether its fractional part is 0).
f_i = 100.0 print(type(f_i)) # <class 'float'> print(isinstance(f_i, int)) # False print(isinstance(f_i, float)) # True Check if a float value is an integer: is_integer()
The float type provides an is_integer() method, which returns True if the value is an integer and False otherwise.
f = 1.23 print(f.is_integer()) # False f_i = 100.0 print(f_i.is_integer()) # True For example, you can define a function that returns True for integer values (int or float with no fractional part). This function returns False for non-numeric types, such as strings (str).
def is_integer_num(n): if isinstance(n, int): return True if isinstance(n, float): return n.is_integer() return False print(is_integer_num(100)) # True print(is_integer_num(1.23)) # False print(is_integer_num(100.0)) # True print(is_integer_num('100')) # False Check if a numeric string is an integer
To check if a numeric string represents an integer value, you can use the following function.
This function attempts to convert the input to a float. If successful, it calls the is_integer() method and returns the result.
def is_integer(n): try: float(n) except ValueError: return False else: return float(n).is_integer() print(is_integer(100)) # True print(is_integer(100.0)) # True print(is_integer(1.23)) # False print(is_integer('100')) # True print(is_integer('100.0')) # True print(is_integer('1.23')) # False print(is_integer('string')) # False See the following articles for more details on converting strings to numbers and handling exceptions using try ... except ....