Boolean
The boolean data-type is either True or False, which are both reserved keywords in Python. In Python, any variable can be assigned to a boolean using True and False keywords. After assigning any variable to a boolean, we can check its data-type using inbuilt Python type() function.
B1 = True
type(B1)
bool
B2 = False
type(B2)
bool
Note that you cannot use true or false. Python is a case-sensitive language. So using true instead of True will lead to an error (NameError).
a = true # In keyword it is not true but it is True. Similar case for False
---------------------------------------------------------------------------
NameError Traceback (most recent call last)
<ipython-input-3-d816aeb5cbe5> in <module>
----> 1 a = true # In keyword it is not true but it is True. Similar case for False
NameError: name 'true' is not defined
Integer and float as booleans
Using Python’s inbuilt bool() function one can convert any numbers to boolean data type. An integer, float or complex number set to zero returns False, while the same if set to any other number, irrespective of positive or negative value, returns True.
bool(5)
True
bool(0)
False
bool(4 + 5j)
True
bool(-2.156)
True
bool(0.000000)
False
String as booleans
The thing which we did above with numbers, can similarly applied with strings. Strings are anything within the inverted commas(""). If there are some characters inside the string (including space), then the equivalent boolean value will be True. In the other hand, if there are no characters in the string (empty string), then the equivalent boolean value will be False.
bool("You are on Fearless Python.")
True
bool(" ") # Spaces inserted in the inverted commas as a string
True
bool("These are special characters: !@#$%^&*-_+=/")
True
bool("") # Nothing is inside the inverted commas (empty string)
False
This concept is famously called as Truthy and Falsy. This is also used widely in if else statements, which you will learn soon.
Boolean operators in python include- and , or , not
We also use == (equivalent) != (not equivalent) operators.
A = True
a = False
not A
False
not a
True
A == a
False
A != a
True
Few more examples are shown bellow.
s = 1; t = 3
s > t # i.e., checking s is greater than t
False
s = 4; t = 4
s < t # i.e. checking s is less than t
False
s == t
True
s <= t # i.e. checking s is less than equalto t
True
If any one of the operation is true , returns True.
s >= t # i.e. checking s is greater than equal to t
True
For further details on Python data-types we can use the inbuilt help() function.
help(bool())
Help on bool object:
class bool(int)
| bool(x) -> bool
|
| Returns True when the argument x is true, False otherwise.
| The builtins True and False are the only two instances of the class bool.
| The class bool is a subclass of the class int, and cannot be subclassed.
|
| Method resolution order:
| bool
| int
| object
|
| Methods defined here:
|
| __and__(self, value, /)
| Return self&value.
|
| __or__(self, value, /)
| Return self|value.
|
| __rand__(self, value, /)
| Return value&self.
|
| __repr__(self, /)
| Return repr(self).
|
| __ror__(self, value, /)
| Return value|self.
|
| __rxor__(self, value, /)
| Return value^self.
|
| __str__(self, /)
| Return str(self).
|
| __xor__(self, value, /)
| Return self^value.
|
| ----------------------------------------------------------------------
| Static methods defined here:
|
| __new__(*args, **kwargs) from builtins.type
| Create and return a new object. See help(type) for accurate signature.
|
| ----------------------------------------------------------------------
| Methods inherited from int:
|
| __abs__(self, /)
| abs(self)
|
| __add__(self, value, /)
| Return self+value.
|
| __bool__(self, /)
| self != 0
|
| __ceil__(...)
| Ceiling of an Integral returns itself.
|
| __divmod__(self, value, /)
| Return divmod(self, value).
|
| __eq__(self, value, /)
| Return self==value.
|
| __float__(self, /)
| float(self)
|
| __floor__(...)
| Flooring an Integral returns itself.
|
| __floordiv__(self, value, /)
| Return self//value.
|
| __format__(self, format_spec, /)
| Default object formatter.
|
| __ge__(self, value, /)
| Return self>=value.
|
| __getattribute__(self, name, /)
| Return getattr(self, name).
|
| __getnewargs__(self, /)
|
| __gt__(self, value, /)
| Return self>value.
|
| __hash__(self, /)
| Return hash(self).
|
| __index__(self, /)
| Return self converted to an integer, if self is suitable for use as an index into a list.
|
| __int__(self, /)
| int(self)
|
| __invert__(self, /)
| ~self
|
| __le__(self, value, /)
| Return self<=value.
|
| __lshift__(self, value, /)
| Return self<<value.
|
| __lt__(self, value, /)
| Return self<value.
|
| __mod__(self, value, /)
| Return self%value.
|
| __mul__(self, value, /)
| Return self*value.
|
| __ne__(self, value, /)
| Return self!=value.
|
| __neg__(self, /)
| -self
|
| __pos__(self, /)
| +self
|
| __pow__(self, value, mod=None, /)
| Return pow(self, value, mod).
|
| __radd__(self, value, /)
| Return value+self.
|
| __rdivmod__(self, value, /)
| Return divmod(value, self).
|
| __rfloordiv__(self, value, /)
| Return value//self.
|
| __rlshift__(self, value, /)
| Return value<<self.
|
| __rmod__(self, value, /)
| Return value%self.
|
| __rmul__(self, value, /)
| Return value*self.
|
| __round__(...)
| Rounding an Integral returns itself.
| Rounding with an ndigits argument also returns an integer.
|
| __rpow__(self, value, mod=None, /)
| Return pow(value, self, mod).
|
| __rrshift__(self, value, /)
| Return value>>self.
|
| __rshift__(self, value, /)
| Return self>>value.
|
| __rsub__(self, value, /)
| Return value-self.
|
| __rtruediv__(self, value, /)
| Return value/self.
|
| __sizeof__(self, /)
| Returns size in memory, in bytes.
|
| __sub__(self, value, /)
| Return self-value.
|
| __truediv__(self, value, /)
| Return self/value.
|
| __trunc__(...)
| Truncating an Integral returns itself.
|
| bit_length(self, /)
| Number of bits necessary to represent self in binary.
|
| >>> bin(37)
| '0b100101'
| >>> (37).bit_length()
| 6
|
| conjugate(...)
| Returns self, the complex conjugate of any int.
|
| to_bytes(self, /, length, byteorder, *, signed=False)
| Return an array of bytes representing an integer.
|
| length
| Length of bytes object to use. An OverflowError is raised if the
| integer is not representable with the given number of bytes.
| byteorder
| The byte order used to represent the integer. If byteorder is 'big',
| the most significant byte is at the beginning of the byte array. If
| byteorder is 'little', the most significant byte is at the end of the
| byte array. To request the native byte order of the host system, use
| `sys.byteorder' as the byte order value.
| signed
| Determines whether two's complement is used to represent the integer.
| If signed is False and a negative integer is given, an OverflowError
| is raised.
|
| ----------------------------------------------------------------------
| Class methods inherited from int:
|
| from_bytes(bytes, byteorder, *, signed=False) from builtins.type
| Return the integer represented by the given array of bytes.
|
| bytes
| Holds the array of bytes to convert. The argument must either
| support the buffer protocol or be an iterable object producing bytes.
| Bytes and bytearray are examples of built-in objects that support the
| buffer protocol.
| byteorder
| The byte order used to represent the integer. If byteorder is 'big',
| the most significant byte is at the beginning of the byte array. If
| byteorder is 'little', the most significant byte is at the end of the
| byte array. To request the native byte order of the host system, use
| `sys.byteorder' as the byte order value.
| signed
| Indicates whether two's complement is used to represent the integer.
|
| ----------------------------------------------------------------------
| Data descriptors inherited from int:
|
| denominator
| the denominator of a rational number in lowest terms
|
| imag
| the imaginary part of a complex number
|
| numerator
| the numerator of a rational number in lowest terms
|
| real
| the real part of a complex number