Python supplement 03 Python built-in function list Basic Data Type Overhead to see the dictionary text file input and output loop design loop object function object

Author: vamei Source: http://www.cnblogs.com/vamei welcome reprint, please also keep this statement.

 

The Python built-in (built-in) function is created with the running of the python interpreter. In pythonProgramYou 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 objectMap ()Filter () Reduce ()

 

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

Mathematical operations

ABS (-5)# Take the absolute value, that is, 5

Round (2.6)# Rounding to an integer, that is, 3.0

Pow (2, 3)# Equivalent to 2 ** 3. For POW (2, 3, 5), equivalent to 2 ** 3% 5

CMP (2.3, 3.2)# Compare the size of two numbers

Divmod (9, 2)# Return the division result and remainder

Max ([1, 5, 2, 9])# Maximum value

Min ([9, 2,-4, 2])# Minimum value

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

 

Type conversion

INT ("5 ")# Convert to integer

Float (2)# Converting to float

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

STR (0, 2.3)# Convert to string

Complex (3, 9)# Return the plural 3 + 9i

 

Ord ("")# Value corresponding to the "A" Character

CHR (65)# Characters corresponding to the value 65

Unichr (65)# Unicode characters 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 = [1, 2, 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 the value of true

 

 

Sorted ([1, 5, 3])# Return the forward sequence, that is, [1, 3, 5].

Reversed ([1, 5, 3])# Return the reverse sequence, that is, [3, 5, 1]

 

Class, object, attribute

 
# Define class
ClassMe (object ):DefTest (Self ):Print "Hello!"
DefNew_test ():
Print "New hello! "
Me= Me ()
 

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

Getattr (Me, "test ")# Return test attributes

Setattr (Me, "test", new_test)# Set the test attribute to new_test

Delattr (Me, "test ")# Deleting the test attribute

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

Issubclass (Me, object)# Is the me class a subclass of the object class?

 

Compile and execute

Repr (me)# String expression of the returned object

Compile ("Print ('hello')", 'test. py', 'exec ')# Compile a string to become a code object

Eval ("1 + 1 ")# Interpret 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