Beginner python--introduce some built-in methods

1, ABS () to seek absolute value

A=abs ( -10)print(a)#  output:

2. All ()

Used to detect whether the list element is all empty, 0, False

Print # true if all elements of the list are empty, false, or 0 o'clock, the return value is False Print # cannot test dictionary, so returns True
# output: False  True

3. Any ()

Used to detect if the list is all not empty, False, 0

Print # true if all elements of the list are not NULL, FALSE, or 0 o'clock, otherwise false # Output: True

4. Bin ()

Converts an integer or long shape into a binary number

Print # output:0b1010

5, callable ()

Used to check whether an object can be called

Print (Callable (a))  # Output:false

6, Chr () and old ()

This is: Returns the ASCII character corresponding to the number, and returns the ASCII value corresponding to the character.

Print (CHRprint(ord ("w"#  output:a  119

7. Dir ()

Output all built-in methods for this data type

b={}print#output: [' __class__ ', ' __contains__ ', ' __delattr__ ', ' __delitem_ _ ', ' __dir__ ', ' __doc__ ', ' __eq__ ', ' __format__ ', ' __ge__ ', ' __getattribute__ ', ' __getitem__ ', ' __gt__ ', ' __hash__ ', ' __ Init__ ', ' __init_subclass__ ', ' __iter__ ', ' __le__ ', ' __len__ ', ' __lt__ ', ' __ne__ ', ' __new__ ', ' __reduce__ ', ' __reduce_ Ex__ ', ' __repr__ ', ' __setattr__ ', ' __setitem__ ', ' __sizeof__ ', ' __str__ ', ' __subclasshook__ ', ' clear ', ' copy ', ' Fromkeys ', ' get ', ' items ', ' Keys ', ' Pop ', ' Popitem ', ' setdefault ', ' Update ', ' values '

8. EXEC ()

Executes a string dynamically, for example:

x = 10Expr=" "z = 30sum = x + y + zprint (sum)" "defFunc ():#exec executes a piece of code dynamicallyy = 20exec(expr)exec(Expr, {'x': 1,'y': 2})#Modify the data based on the original code to get a different result    exec(Expr, {'x': 1,'y': 2}, {'y': 3,'Z': 4}) func ()#Output:60 33 34

9. Lambda

anonymous functions

c=Lambda# anonymous function print# anonymous function call and pass the parameter print(lambda  # parameter invocation of anonymous functions
# Output:  7

10. Filter ()

The function of the filter function is to filter out the data you want.

The function of the Res=filter (Lambda#filter function is to filter out the data you want for the in   Res:     Print (i)

Output: 6 7 8 9

11, Globals ()

Output all the variables of the entire program, returning a dictionary. The variable name is key and the value is

12, Max (), Min ()

Returns the maximum and minimum values in the list

d=[5,6,12]print# returns the maximum value in the list print# Returns the minimum value of the table

Output: 12 5

13. Oct ()

Converts a decimal number to eight binary numbers

Print (Oct (5)) Print (Oct  ) # Convert decimal to 8 binary # Output: 0o50o12

14. Pow ()

Calculate the exponentiation

Print # 2 of the 8-time Square #  the

15, round ()

Keep floating-point numbers in n decimal places

Print # Keep floating-point numbers 3 decimal places # output:3.568

16. SUM ()

Sum the list

Print # list Sum #  at

17, Sorted ()

Sort all the objects that can be iterated

Sorted (iterable, Cmp=none, Key=none, Reverse=false)--New sorted list

Iterable: is an iterative type;
CMP: A function For comparison, comparing what is determined by key;
Key: A property or function of a list element that is used as a keyword with a default value that iterates over an item in the collection;
Reverse: Sorting rules. Reverse = True descending or reverse = False Ascending, default ascending;
Return value: Is a sorted, iterative type, as with iterable.

(1) Sort by element length

L = [{1:5,3:4},{1:3,6:3},{1:1,2:4,5:6},{1:9}]def  F (x):    return  len (x) Sort (Key=print  (L)#  Output:[{1:9}, {1:5, 3:4}, {1:3, 6:3}, {1:1, 2: 4, 5:6}]

(2) Sort by one of the values in the element, for example:

Students = [(' John ', ' A ', '), (' Jane ', ' B ', '), (' Dave ', ' B ', 10),]

Sort by age:

① using the key function to sort

Sorted (students, key=Lambda x:x[2#

② using CMP functions to sort

Sorted (students, cmp=Lambda x,y:cmp (x[2], y[2]  )#

18. zip ()

Pull two lists together to form a zip data type

a=[1,2,3,4]b=["a","b","C","D"]Print(Zip (A, b))#pull two lists together to form a zip data type forIinchZip (A, b):Print(i)#<zip object at 0x00000249f0946d48>

19, __import__ ()

Another way to invoke the module, which is written in parentheses, is the module's name string

Beginner python--introduce some built-in methods