python basis of a built-in function day16

# Data Type: int bool. . . 
# Data structure: dict list tuple set str


the reversed () 
L = [1,2,3,4,5] 
l.reverse () 
Print (L) 
L = [1,2,3,4,5] 
L2 = the reversed (L) 
Print (L2) 
to retain the original list, returns a reverse iterator 

L = (1,2,23,213,5612,342,43) 
SLI = Slice (1,5,2) 
Print (L [SLI]) 
Print (L [. 1:. 5: 2 ]) 

Print (the format ( 'Test', '<20 is')) 
Print (the format ( 'Test', '> 40')) 
Print (the format ( 'Test', '^ 40')) 

bytes is converted into bytes type 
I gbk get is encoded, I want to turn to a utf-8 encoded 
print (bytes ( 'Hello', encoding = 'GBK') ) # unicode GBK is converted into bytes 
print (bytes ( 'Hello', encoding = 'utf-8')) # unicode bytes utf-8 converted into the 

network only transmit binary programming 
photos and videos are stored in binary 
html pages are crawled to encode 
b_array = bytearray ( 'Hello', encoding = 'utf -8')
print(b_array)
print(b_array[0])
'\ XE4 \ XBD \ XA0 \ xe5 \ xa5 \ XBD' 
S1 = 'ALEXA' 
S2 = 'alexb' 

L = 'ahfjskjlyhtgeoahwkvnadlnv' 
L2 = L [: 10] 

Slice - byte memory type does not occupy 
bytes - Character string per memory 

print (ord ( 'good')) 
print (ord ( '. 1')) 
Print (CHR (97)) 

Print (ASCII ( 'good')) 
Print (ASCII ( '. 1')) 
name = 'Egg ' 
Print (' Hello R & lt% '% name) 
Print (the repr ('. 1 ')) 
Print (the repr (. 1)) 

Print (All ([' A ',' ', 123])) 
Print (All ([' A ', 123])) 
Print (All ([0,123])) 

Print (the any ([' ', True, 0, []])) 

L = [1,2,3,4,5] 
L2 = [' A ',' B ',' C ',' D '] 
L3 = (' * ',' ** ', [1,2]) 
D = {'k1':1,'k2':2}
for i in zip(l,l2,l3,d):
    print(i)

def is_odd(x):
    . 1% 2 == X return 

DEF is_str (S): 
    return S and STR (S) .strip () 

RET = filter (is_odd, [. 1,. 6,. 7, 12 is,. 17]) 
RET = filter (is_str, [. 1 , 'Hello', '', '', None, [],. 6,. 7, 'World', 12 is,. 17]) 
Print (RET) 
for I in RET: 
    Print (I) 
[I for I in [. 1, . 4,. 6,. 7,. 9, 12 is,. 17] == 2% IF I. 1] 

from Math Import sqrt 
DEF FUNC (NUM): 
    RES = sqrt (NUM) 
    return RES == 0. 1% 
RET = filter (FUNC, Range (1,101)) 
for I in RET: 
    Print (I) 


RET = Map (ABS, [. 1, 4,6, -8]) 
Print (RET) 
for I in RET: 
    Print (I) 


filter after the filter is performed result set <= the number before performing 
        filter just filtering, does not alter the value of 
the number of elements performing the same before and after the map 
      value may change

= L [. 1, -4,6,5, -10] 
# l.sort (Key = ABS) # sort list on the basis of the original 
# Print (L) 

Print (the sorted (L, Key = ABS, Reverse = True )) # generates a new list without changing the original list total memory 
Print (L) 

L = [ '', [1,2], 'Hello World'] 
new_l the sorted = (L, Key = len) 
Print (new_l)

python basis of a built-in function day16

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