Python quick tutorial (supplement 03): Python built-in function list

The Python built-in (built-in) function is created with the running of the python interpreter. In Python programs, you can call these functions at any time without defining them. The most common built-in functions are: The Python built-in (built-in) functions are created with the running of the python interpreter. In Python programs, you can call these functions at any time without defining them. The most common built-in functions are:

PRint ("Hello World !")

In the Python tutorial, we have mentioned the following built-in functions:

Basic data type ()

Look at dir () help () len ()

Dictionary len ()

Text file input and output open ()

Loop design range () enumerate () zip ()

Loop object iter ()

Function Object map () filter () reduce ()

The following are all actual parameters. you can try the results directly on the command line.

Mathematical operations

Abs (-5) # obtain the absolute value, that is, 5

Round (2.6) # round the round, that is, 3.0

Pow (2, 3) # is equivalent to 2 ** 3. if it is pow (2, 3, 5), it is equivalent to 2 ** 3% 5

Cmp (2.3, 3.2) # compare the two numbers

Pmod () # returns the division result and remainder

Max ([,]) # calculate the maximum value

Min ([,-]) # calculate the minimum value

Sum ([2,-1, 9, 12]) # sum

Type conversion

Int ("5") # Convert to integer

Float (2) # Convert to float

Long ("23") # Convert to a long integer

Str (2.3) # Convert to string

Complex (3, 9) # returns the plural number 3 + 9i

Ord ("A") # The value corresponding to the "A" character

Chr (65) # character corresponding to the value 65

Unichr (65) # unicode character corresponding to the value 65

Bool (0) # convert to the corresponding real value. in Python, 0 is equivalent to False.

In Python, the following objects are equivalent to False: [], (), {}, 0, None, 0.0 ,"

Bin (56) # returns a string that represents the number of bits 56

Hex (56) # returns a string representing the hexadecimal number of 56.

Oct (56) # returns a string that represents the number of octal digits of 56.

List (1, 2, 3) # Convert to table list

Tuple ([2, 3, 4]) # Convert to a value table tuple

Slice (5, 2,-1) # construct the subscript object slice

Dict (a = 1, B = "hello", c = [, 3]) # Build a dictionary

Sequential operation

All ([True, 1, "hello! "]) # Whether all elements are equivalent to True

Any (["", 0, False, [], None]) # whether any element is equal to True

Sorted ([, 3]) # returns the sequence in the forward order, that is, [, 5].

Reversed ([, 3]) # returns the reverse sequence, that is, [, 1].

Class, object, attribute

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# Define class

Class Me (object ):

Def test (self ):

Print "Hello! "

Def new_test ():

Print "New Hello! "

Me = Me ()

Hasattr (me, "test") # check whether the me object has the test attribute

Getattr (me, "test") # returns the test attribute.

Setattr (me, "test", new_test) # set the test attribute to new_test

Delattr (me, "test") # Delete the test attribute

Isinstance (me, Me) # whether the me object is an object generated by the Me class (an instance)

Issubclass (Me, object) # whether the Me class is a subclass of the object class

Compile and execute

Repr (me) # returns the string expression of the object

Compile ("print ('Hello')", 'Test. py', 'exec ') # compile the string to become a code object

Eval ("1 + 1") # interprets string expressions. The parameter can also be the code object returned by compile ().

Exec ("print ('Hello')") # interpret and execute the string, print ('Hello '). The parameter can also be the code object returned by compile ().

Others

Input ("Please input:") # waiting for input

Globals () # return the global namespace, such as the global variable name and global function name.

Locals () # return a local namespace