python-3_ Function _ anonymous function _ Regular _yield_ Iterator _ serialization _ built-in function _ module

L=[' A ', ' B ', ' C ', ' d ']

for (Offset,item) in Enumerate (L):
Print Offset,item

Printed results:

2 #
1 b
2 C
4 D


Iterators:

For I in range (100): Generate list

For I in xrange (100) iterators, faster than range

ReadLines () Xreadlines ()

Example:

def run ():
Print "Test1"
Yield 1 #变成迭代器, the program runs here will stop jumping out of execution. Yield is the equivalent of the return value.
Time.sleep (1)
Print "Test2"
Time.sleep (1)
Print "Test2"
Time.sleep (1)
Print "Test2"
Time.sleep (1)

Task=run ()
Task.next ()
print '--do sth else---'
Task.next () #如果不加本行, it will not execute after yield.


Function:

Lambda function (anonymous function):

def f (x):
Return x**2
g = The notation of the lambda x:x**2 anonymous function

Print map (F,range (10)) the list input function operation, and then return the result
Print map (lambda X:x**2,range (10))

Sorted () Usage: example is to sort the dictionary key (although the dictionary is unordered)

Dic1={3:2,4:3,6:9, ' A ': ' Test ', ' e ': ' FFF ', ' * ': ' $ '}
Print sorted (Dic1.items (), Key=lambda x:x[0])
RGS Kargs


Built-in functions:

A=range (10)
A=iter (a) #把列表变成了迭代器
A.next ()

print [i-I in a if a<5]
Filter (lambda x:x*x,a)



Serialization:
Only strings or binaries can be stored on the hard disk, so dictionaries, lists, etc. cannot be saved.
Pickle is just the type of serialization used in Python.

Pickle.dump (object, file handle) Pickle.load () pickle.dump (dic1,f)
Json.dump () Json.load ()

Regular Expressions:

m = Re.match ("\d", matching object) match is matched from the beginning.
View match to Character: M.group ()

Re.search () Global lookup match

Re.findall () finds all matches to the
Re.split () split by symbol
Re.sub (' \d ', ' | ', character object) Replace the comb with |
Re.sub (' \d ', ' | ', character object, count=2) only replace the first two

Module creation and import:

If __name__== ' __main__ ' active execution will execute, import does not execute

Common modules:
Import SYS
Sys.path
Sys.path
Sys.exit

Import OS
Os.system (' uname ')
Os.mkdir (' MyDir ')
Os.chdir (' ~ ')

python-3_ Function _ anonymous function _ Regular _yield_ Iterator _ serialization _ built-in function _ module