1. Built-in functions

Function	description	input	output	change
dir()	show all the varibales and functions(mehtods) in the object	object	list;['variables', fucntions]	X
id()	return the memory address	object	int	X
len()	return the number of imtes in container	container	int	X
min()	return the minimum of an iterable data	iterable	object	X
max()	return the maximum of an iterable data	iterable	object	X
ord()	return the unicode poinit	chr	int	X
sum()	return the sum of an iterable data	iterable	int	X
type()	return the type of object	object	type	X

2. Built-in functions2

delete object
```
del obj_name
```
delete (items in list) or (key in dict)
```
del my_list[0]
del my_dict['name']
```

formating

print('%d %f', %(200, 3.4))
print('{:d} {:f}' .format(200, 3.4))
print(f'{200:d} {3.4:f}')

conversion specifier applications

specifier	conversion
%10d, %5f, %20s %>10d, %>5f, %>20s	width of the field right aligned
%010d, %05f, %020s	width of the field right aligned fill left with 0
%-10d, %-5f, %-20s %<10d, %<5f, %<20s	width of the field left aligned
%^10d, %^5f, %^20s	width of the field center aligned
%.2f, %5.2f	width of the field decimal place of the float
%.3s, %10.2s	width of the field num of printed chr from the left

return iterable elements paired with int that start with 'start' parameter

apply the function to all the elements of iterable object * return map object

apply the function to all the elments of iterable object, and remain elemetns which are ture * return filter object

pair elements in different iterable object according to its index number

used for defining a simple function