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Python Built-in FunctionsThe Python built-in functions are defined as the functions whose functionality is pre-defined in Python. The python interpreter has several functions that are always present for use. These functions are known as Built-in Functions. There are several built-in functions in Python which are listed below: Python abs() FunctionThe python abs() function is used to return the absolute value of a number. It takes only one argument, a number whose absolute value is to be returned. The argument can be an integer and floating-point number. If the argument is a complex number, then, abs() returns its magnitude. Python abs() Function Example # integer number integer = -20 print('Absolute value of -40 is:', abs(integer)) # floating number floating = -20.83 print('Absolute value of -40.83 is:', abs(floating)) Output: Absolute value of -20 is: 20 Absolute value of -20.83 is: 20.83 Python all() FunctionThe python all() function accepts an iterable object (such as list, dictionary, etc.). It returns true if all items in passed iterable are true. Otherwise, it returns False. If the iterable object is empty, the all() function returns True. Python all() Function Example # all values true k = [1, 3, 4, 6] print(all(k)) # all values false k = [0, False] print(all(k)) # one false value k = [1, 3, 7, 0] print(all(k)) # one true value k = [0, False, 5] print(all(k)) # empty iterable k = [] print(all(k)) Output: True False False False True Python bin() FunctionThe python bin() function is used to return the binary representation of a specified integer. A result always starts with the prefix 0b. Python bin() Function Example x = 10 y = bin(x) print (y) Output: 0b1010 Python bool()The python bool() converts a value to boolean(True or False) using the standard truth testing procedure. Python bool() Example test1 = [] print(test1,'is',bool(test1)) test1 = [0] print(test1,'is',bool(test1)) test1 = 0.0 print(test1,'is',bool(test1)) test1 = None print(test1,'is',bool(test1)) test1 = True print(test1,'is',bool(test1)) test1 = 'Easy string' print(test1,'is',bool(test1)) Output: [] is False [0] is True 0.0 is False None is False True is True Easy string is True Python bytes()The python bytes() in Python is used for returning a bytes object. It is an immutable version of the bytearray() function. It can create empty bytes object of the specified size. Python bytes() Example string = "Hello World." array = bytes(string, 'utf-8') print(array) Output: b ' Hello World.' Python callable() FunctionA python callable() function in Python is something that can be called. This built-in function checks and returns true if the object passed appears to be callable, otherwise false. Python callable() Function Example x = 8 print(callable(x)) Output: False Python compile() FunctionThe python compile() function takes source code as input and returns a code object which can later be executed by exec() function. Python compile() Function Example # compile string source to code code_str = 'x=5\ny=10\nprint("sum =",x+y)' code = compile(code_str, 'sum.py', 'exec') print(type(code)) exec(code) exec(x) Output: <class 'code'> sum = 15 Python exec() FunctionThe python exec() function is used for the dynamic execution of Python program which can either be a string or object code and it accepts large blocks of code, unlike the eval() function which only accepts a single expression. Python exec() Function Example x = 8 exec('print(x==8)') exec('print(x+4)') Output: True 12 Python sum() FunctionAs the name says, python sum() function is used to get the sum of numbers of an iterable, i.e., list. Python sum() Function Example s = sum([1, 2,4 ]) print(s) s = sum([1, 2, 4], 10) print(s) Output: 7 17 Python any() FunctionThe python any() function returns true if any item in an iterable is true. Otherwise, it returns False. Python any() Function Example l = [4, 3, 2, 0] print(any(l)) l = [0, False] print(any(l)) l = [0, False, 5] print(any(l)) l = [] print(any(l)) Output: True False True False Python ascii() FunctionThe python ascii() function returns a string containing a printable representation of an object and escapes the non-ASCII characters in the string using \x, \u or \U escapes. Python ascii() Function Example normalText = 'Python is interesting' print(ascii(normalText)) otherText = 'Pyth�n is interesting' print(ascii(otherText)) print('Pyth\xf6n is interesting') Output: 'Python is interesting' 'Pyth\xf6n is interesting' Pyth�n is interesting Python bytearray()The python bytearray() returns a bytearray object and can convert objects into bytearray objects, or create an empty bytearray object of the specified size. Python bytearray() Example string = "Python is a programming language." # string with encoding 'utf-8' arr = bytearray(string, 'utf-8') print(arr) Output: bytearray(b'Python is a programming language.') Python eval() FunctionThe python eval() function parses the expression passed to it and runs python expression(code) within the program. Python eval() Function Example x = 8 print(eval('x + 1')) Output: 9 Python float()The python float() function returns a floating-point number from a number or string. Python float() Example # for integers print(float(9)) # for floats print(float(8.19)) # for string floats print(float("-24.27")) # for string floats with whitespaces print(float(" -17.19\n")) # string float error print(float("xyz")) Output: 9.0 8.19 -24.27 -17.19 ValueError: could not convert string to float: 'xyz' Python format() FunctionThe python format() function returns a formatted representation of the given value. Python format() Function Example # d, f and b are a type # integer print(format(123, "d")) # float arguments print(format(123.4567898, "f")) # binary format print(format(12, "b")) Output: 123 123.456790 1100 Python frozenset()The python frozenset() function returns an immutable frozenset object initialized with elements from the given iterable. Python frozenset() Example # tuple of letters letters = ('m', 'r', 'o', 't', 's') fSet = frozenset(letters) print('Frozen set is:', fSet) print('Empty frozen set is:', frozenset()) Output: Frozen set is: frozenset({'o', 'm', 's', 'r', 't'}) Empty frozen set is: frozenset() Python getattr() FunctionThe python getattr() function returns the value of a named attribute of an object. If it is not found, it returns the default value. Python getattr() Function Example class Details: age = 22 name = "Phill" details = Details() print('The age is:', getattr(details, "age")) print('The age is:', details.age) Output: The age is: 22 The age is: 22 Python globals() FunctionThe python globals() function returns the dictionary of the current global symbol table. A Symbol table is defined as a data structure which contains all the necessary information about the program. It includes variable names, methods, classes, etc. Python globals() Function Example age = 22 globals()['age'] = 22 print('The age is:', age) Output: The age is: 22 Python hasattr() FunctionThe python any() function returns true if any item in an iterable is true, otherwise it returns False. Python hasattr() Function Example l = [4, 3, 2, 0] print(any(l)) l = [0, False] print(any(l)) l = [0, False, 5] print(any(l)) l = [] print(any(l)) Output: True False True False Python iter() FunctionThe python iter() function is used to return an iterator object. It creates an object which can be iterated one element at a time. Python iter() Function Example # list of numbers list = [1,2,3,4,5] listIter = iter(list) # prints '1' print(next(listIter)) # prints '2' print(next(listIter)) # prints '3' print(next(listIter)) # prints '4' print(next(listIter)) # prints '5' print(next(listIter)) Output: 1 2 3 4 5 Python len() FunctionThe python len() function is used to return the length (the number of items) of an object. Python len() Function Example strA = 'Python' print(len(strA)) Output: 6 Python list()The python list() creates a list in python. Python list() Example # empty list print(list()) # string String = 'abcde' print(list(String)) # tuple Tuple = (1,2,3,4,5) print(list(Tuple)) # list List = [1,2,3,4,5] print(list(List)) Output: [] ['a', 'b', 'c', 'd', 'e'] [1,2,3,4,5] [1,2,3,4,5] Python locals() FunctionThe python locals() method updates and returns the dictionary of the current local symbol table. A Symbol table is defined as a data structure which contains all the necessary information about the program. It includes variable names, methods, classes, etc. Python locals() Function Example def localsAbsent(): return locals() def localsPresent(): present = True return locals() print('localsNotPresent:', localsAbsent()) print('localsPresent:', localsPresent()) Output: localsAbsent: {} localsPresent: {'present': True} Python map() FunctionThe python map() function is used to return a list of results after applying a given function to each item of an iterable(list, tuple etc.). Python map() Function Example def calculateAddition(n): return n+n numbers = (1, 2, 3, 4) result = map(calculateAddition, numbers) print(result) # converting map object to set numbersAddition = set(result) print(numbersAddition) Output: <map object at 0x7fb04a6bec18> {8, 2, 4, 6} Python memoryview() FunctionThe python memoryview() function returns a memoryview object of the given argument. Python memoryview () Function Example #A random bytearray randomByteArray = bytearray('ABC', 'utf-8') mv = memoryview(randomByteArray) # access the memory view's zeroth index print(mv[0]) # It create byte from memory view print(bytes(mv[0:2])) # It create list from memory view print(list(mv[0:3])) Output: 65 b'AB' [65, 66, 67] Python object()The python object() returns an empty object. It is a base for all the classes and holds the built-in properties and methods which are default for all the classes. Python object() Example python = object() print(type(python)) print(dir(python)) Output: <class 'object'> ['__class__', '__delattr__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__gt__', '__hash__', '__init__', '__le__', '__lt__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__'] Python open() FunctionThe python open() function opens the file and returns a corresponding file object. Python open() Function Example # opens python.text file of the current directory f = open("python.txt") # specifying full path f = open("C:/Python33/README.txt") Output: Since the mode is omitted, the file is opened in 'r' mode; opens for reading. Python chr() FunctionPython chr() function is used to get a string representing a character which points to a Unicode code integer. For example, chr(97) returns the string 'a'. This function takes an integer argument and throws an error if it exceeds the specified range. The standard range of the argument is from 0 to 1,114,111. Python chr() Function Example # Calling function result = chr(102) # It returns string representation of a char result2 = chr(112) # Displaying result print(result) print(result2) # Verify, is it string type? print("is it string type:", type(result) is str) Output: ValueError: chr() arg not in range(0x110000) Python complex()Python complex() function is used to convert numbers or string into a complex number. This method takes two optional parameters and returns a complex number. The first parameter is called a real and second as imaginary parts. Python complex() Example # Python complex() function example # Calling function a = complex(1) # Passing single parameter b = complex(1,2) # Passing both parameters # Displaying result print(a) print(b) Output: (1.5+0j) (1.5+2.2j) Python delattr() FunctionPython delattr() function is used to delete an attribute from a class. It takes two parameters, first is an object of the class and second is an attribute which we want to delete. After deleting the attribute, it no longer available in the class and throws an error if try to call it using the class object. Python delattr() Function Example class Student: id = 101 name = "Pranshu" email = "pranshu@abc.com" # Declaring function def getinfo(self): print(self.id, self.name, self.email) s = Student() s.getinfo() delattr(Student,'course') # Removing attribute which is not available s.getinfo() # error: throws an error Output: 101 Pranshu [email protected] AttributeError: course Python dir() FunctionPython dir() function returns the list of names in the current local scope. If the object on which method is called has a method named __dir__(), this method will be called and must return the list of attributes. It takes a single object type argument. Python dir() Function Example # Calling function att = dir() # Displaying result print(att) Output: ['__annotations__', '__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__spec__'] Python divmod() FunctionPython divmod() function is used to get remainder and quotient of two numbers. This function takes two numeric arguments and returns a tuple. Both arguments are required and numeric Python divmod() Function Example # Python divmod() function example # Calling function result = divmod(10,2) # Displaying result print(result) Output: (5, 0) Python enumerate() FunctionPython enumerate() function returns an enumerated object. It takes two parameters, first is a sequence of elements and the second is the start index of the sequence. We can get the elements in sequence either through a loop or next() method. Python enumerate() Function Example # Calling function result = enumerate([1,2,3]) # Displaying result print(result) print(list(result)) Output: <enumerate object at 0x7ff641093d80> [(0, 1), (1, 2), (2, 3)] Python dict()Python dict() function is a constructor which creates a dictionary. Python dictionary provides three different constructors to create a dictionary:
Python dict() Example # Calling function result = dict() # returns an empty dictionary result2 = dict(a=1,b=2) # Displaying result print(result) print(result2) Output: {} {'a': 1, 'b': 2} Python filter() FunctionPython filter() function is used to get filtered elements. This function takes two arguments, first is a function and the second is iterable. The filter function returns a sequence of those elements of iterable object for which function returns true value. The first argument can be none, if the function is not available and returns only elements that are true. Python filter() Function Example # Python filter() function example def filterdata(x): if x>5: return x # Calling function result = filter(filterdata,(1,2,6)) # Displaying result print(list(result)) Output: [6] Python hash() FunctionPython hash() function is used to get the hash value of an object. Python calculates the hash value by using the hash algorithm. The hash values are integers and used to compare dictionary keys during a dictionary lookup. We can hash only the types which are given below: Hashable types: * bool * int * long * float * string * Unicode * tuple * code object. Python hash() Function Example # Calling function result = hash(21) # integer value result2 = hash(22.2) # decimal value # Displaying result print(result) print(result2) Output: 21 461168601842737174 Python help() FunctionPython help() function is used to get help related to the object passed during the call. It takes an optional parameter and returns help information. If no argument is given, it shows the Python help console. It internally calls python's help function. Python help() Function Example # Calling function info = help() # No argument # Displaying result print(info) Output: Welcome to Python 3.5's help utility! Python min() FunctionPython min() function is used to get the smallest element from the collection. This function takes two arguments, first is a collection of elements and second is key, and returns the smallest element from the collection. Python min() Function Example # Calling function small = min(2225,325,2025) # returns smallest element small2 = min(1000.25,2025.35,5625.36,10052.50) # Displaying result print(small) print(small2) Output: 325 1000.25 Python set() FunctionIn python, a set is a built-in class, and this function is a constructor of this class. It is used to create a new set using elements passed during the call. It takes an iterable object as an argument and returns a new set object. Python set() Function Example # Calling function result = set() # empty set result2 = set('12') result3 = set('TheDeveloperBlog') # Displaying result print(result) print(result2) print(result3) Output: set() {'1', '2'} {'a', 'n', 'v', 't', 'j', 'p', 'i', 'o'} Python hex() FunctionPython hex() function is used to generate hex value of an integer argument. It takes an integer argument and returns an integer converted into a hexadecimal string. In case, we want to get a hexadecimal value of a float, then use float.hex() function. Python hex() Function Example # Calling function result = hex(1) # integer value result2 = hex(342) # Displaying result print(result) print(result2) Output: 0x1 0x156 Python id() FunctionPython id() function returns the identity of an object. This is an integer which is guaranteed to be unique. This function takes an argument as an object and returns a unique integer number which represents identity. Two objects with non-overlapping lifetimes may have the same id() value. Python id() Function Example # Calling function val = id("TheDeveloperBlog") # string object val2 = id(1200) # integer object val3 = id([25,336,95,236,92,3225]) # List object # Displaying result print(val) print(val2) print(val3) Output: 139963782059696 139963805666864 139963781994504 Python setattr() FunctionPython setattr() function is used to set a value to the object's attribute. It takes three arguments, i.e., an object, a string, and an arbitrary value, and returns none. It is helpful when we want to add a new attribute to an object and set a value to it. Python setattr() Function Example class Student: id = 0 name = "" def __init__(self, id, name): self.id = id self.name = name student = Student(102,"Sohan") print(student.id) print(student.name) #print(student.email) product error setattr(student, 'email','sohan@abc.com') # adding new attribute print(student.email) Output: 102 Sohan [email protected] Python slice() FunctionPython slice() function is used to get a slice of elements from the collection of elements. Python provides two overloaded slice functions. The first function takes a single argument while the second function takes three arguments and returns a slice object. This slice object can be used to get a subsection of the collection. Python slice() Function Example # Calling function result = slice(5) # returns slice object result2 = slice(0,5,3) # returns slice object # Displaying result print(result) print(result2) Output: slice(None, 5, None) slice(0, 5, 3) Python sorted() FunctionPython sorted() function is used to sort elements. By default, it sorts elements in an ascending order but can be sorted in descending also. It takes four arguments and returns a collection in sorted order. In the case of a dictionary, it sorts only keys, not values. Python sorted() Function Example str = "TheDeveloperBlog" # declaring string # Calling function sorted1 = sorted(str) # sorting string # Displaying result print(sorted1) Output: ['a', 'a', 'i', 'j', 'n', 'o', 'p', 't', 't', 'v'] Python next() FunctionPython next() function is used to fetch next item from the collection. It takes two arguments, i.e., an iterator and a default value, and returns an element. This method calls on iterator and throws an error if no item is present. To avoid the error, we can set a default value. Python next() Function Example number = iter([256, 32, 82]) # Creating iterator # Calling function item = next(number) # Displaying result print(item) # second item item = next(number) print(item) # third item item = next(number) print(item) Output: 256 32 82 Python input() FunctionPython input() function is used to get an input from the user. It prompts for the user input and reads a line. After reading data, it converts it into a string and returns it. It throws an error EOFError if EOF is read. Python input() Function Example # Calling function val = input("Enter a value: ") # Displaying result print("You entered:",val) Output: Enter a value: 45 You entered: 45 Python int() FunctionPython int() function is used to get an integer value. It returns an expression converted into an integer number. If the argument is a floating-point, the conversion truncates the number. If the argument is outside the integer range, then it converts the number into a long type. If the number is not a number or if a base is given, the number must be a string. Python int() Function Example # Calling function val = int(10) # integer value val2 = int(10.52) # float value val3 = int('10') # string value # Displaying result print("integer values :",val, val2, val3) Output: integer values : 10 10 10 Python isinstance() FunctionPython isinstance() function is used to check whether the given object is an instance of that class. If the object belongs to the class, it returns true. Otherwise returns False. It also returns true if the class is a subclass. The isinstance() function takes two arguments, i.e., object and classinfo, and then it returns either True or False. Python isinstance() function Example class Student: id = 101 name = "John" def __init__(self, id, name): self.id=id self.name=name student = Student(1010,"John") lst = [12,34,5,6,767] # Calling function print(isinstance(student, Student)) # isinstance of Student class print(isinstance(lst, Student)) Output: True False Python oct() FunctionPython oct() function is used to get an octal value of an integer number. This method takes an argument and returns an integer converted into an octal string. It throws an error TypeError, if argument type is other than an integer. Python oct() function Example # Calling function val = oct(10) # Displaying result print("Octal value of 10:",val) Output: Octal value of 10: 0o12 Python ord() FunctionThe python ord() function returns an integer representing Unicode code point for the given Unicode character. Python ord() function Example # Code point of an integer print(ord('8')) # Code point of an alphabet print(ord('R')) # Code point of a character print(ord('&')) Output: 56 82 38 Python pow() FunctionThe python pow() function is used to compute the power of a number. It returns x to the power of y. If the third argument(z) is given, it returns x to the power of y modulus z, i.e. (x, y) % z. Python pow() function Example # positive x, positive y (x**y) print(pow(4, 2)) # negative x, positive y print(pow(-4, 2)) # positive x, negative y (x**-y) print(pow(4, -2)) # negative x, negative y print(pow(-4, -2)) Output: 16 16 0.0625 0.0625 Python print() FunctionThe python print() function prints the given object to the screen or other standard output devices. Python print() function Example print("Python is programming language.") x = 7 # Two objects passed print("x =", x) y = x # Three objects passed print('x =', x, '= y') Output: Python is programming language. x = 7 x = 7 = y Python range() FunctionThe python range() function returns an immutable sequence of numbers starting from 0 by default, increments by 1 (by default) and ends at a specified number. Python range() function Example # empty range print(list(range(0))) # using the range(stop) print(list(range(4))) # using the range(start, stop) print(list(range(1,7 ))) Output: [] [0, 1, 2, 3] [1, 2, 3, 4, 5, 6] Python reversed() FunctionThe python reversed() function returns the reversed iterator of the given sequence. Python reversed() function Example # for string String = 'Java' print(list(reversed(String))) # for tuple Tuple = ('J', 'a', 'v', 'a') print(list(reversed(Tuple))) # for range Range = range(8, 12) print(list(reversed(Range))) # for list List = [1, 2, 7, 5] print(list(reversed(List))) Output: ['a', 'v', 'a', 'J'] ['a', 'v', 'a', 'J'] [11, 10, 9, 8] [5, 7, 2, 1] Python round() FunctionThe python round() function rounds off the digits of a number and returns the floating point number. Python round() Function Example # for integers print(round(10)) # for floating point print(round(10.8)) # even choice print(round(6.6)) Output: 10 11 7 Python issubclass() FunctionThe python issubclass() function returns true if object argument(first argument) is a subclass of second class(second argument). Python issubclass() Function Example class Rectangle: def __init__(rectangleType): print('Rectangle is a ', rectangleType) class Square(Rectangle): def __init__(self): Rectangle.__init__('square') print(issubclass(Square, Rectangle)) print(issubclass(Square, list)) print(issubclass(Square, (list, Rectangle))) print(issubclass(Rectangle, (list, Rectangle))) Output: True False True True Python strThe python str() converts a specified value into a string. Python str() Function Example str('4') Output: '4' Python tuple() FunctionThe python tuple() function is used to create a tuple object. Python tuple() Function Example t1 = tuple() print('t1=', t1) # creating a tuple from a list t2 = tuple([1, 6, 9]) print('t2=', t2) # creating a tuple from a string t1 = tuple('Java') print('t1=',t1) # creating a tuple from a dictionary t1 = tuple({4: 'four', 5: 'five'}) print('t1=',t1) Output: t1= () t2= (1, 6, 9) t1= ('J', 'a', 'v', 'a') t1= (4, 5) Python type()The python type() returns the type of the specified object if a single argument is passed to the type() built in function. If three arguments are passed, then it returns a new type object. Python type() Function Example List = [4, 5] print(type(List)) Dict = {4: 'four', 5: 'five'} print(type(Dict)) class Python: a = 0 InstanceOfPython = Python() print(type(InstanceOfPython)) Output: <class 'list'> <class 'dict'> <class '__main__.Python'> Python vars() functionThe python vars() function returns the __dict__ attribute of the given object. Python vars() Function Example class Python: def __init__(self, x = 7, y = 9): self.x = x self.y = y InstanceOfPython = Python() print(vars(InstanceOfPython)) Output: {'y': 9, 'x': 7} Python zip() FunctionThe python zip() Function returns a zip object, which maps a similar index of multiple containers. It takes iterables (can be zero or more), makes it an iterator that aggregates the elements based on iterables passed, and returns an iterator of tuples. Python zip() Function Example numList = [4,5, 6] strList = ['four', 'five', 'six'] # No iterables are passed result = zip() # Converting itertor to list resultList = list(result) print(resultList) # Two iterables are passed result = zip(numList, strList) # Converting itertor to set resultSet = set(result) print(resultSet) Output: [] {(5, 'five'), (4, 'four'), (6, 'six')}
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