18 个 Python 编程技巧,提高工作效率

>>>a=3  

>>>b=6

>>>a,b=b,a  

>>>print(a)>>>6  

>>>ptint(b)>>>5

>>> some_list = \[1, 2, 3, 4, 5\]  

>>> another_list = \[ x + 1 for x in some_list \]  

>>> another_list  
\[2, 3, 4, 5, 6\]

>>> # Set Comprehensions  
>>> some_list = \[1, 2, 3, 4, 5, 2, 5, 1, 4, 8\]  

>>> even_set = { x for x in some_list if x % 2 == 0 }  

>>> even_set  
set(\[8, 2, 4\])  

>>> # Dict Comprehensions  

>>> d = { x: x % 2 == 0 for x in range(1, 11) }  

>>> d  
{1: False, 2: True, 3: False, 4: True, 5: False, 6: True, 7: False, 8: True, 9: False, 10: True}

>>> my_set = {1, 2, 1, 2, 3, 4}  

>>> my_set  
set(\[1, 2, 3, 4\])  

>>> from collections import Counter  
>>> c = Counter( hello world )  

>>> c  
Counter({ l : 3,  o : 2,   : 1,  e : 1,  d : 1,  h : 1,  r : 1,  w : 1})  

>>> c.most_common(2)  
\[( l , 3), ( o , 2)\]  

>>> import json  

>>> print(json.dumps(data))  # No indention  
{"status": "OK", "count": 2, "results": \[{"age": 27, "name": "Oz", "lactose_intolerant": true}, {"age": 29, "name": "Joe", "lactose_intolerant": false}\]}  

>>> print(json.dumps(data, indent=2))  # With indention  

{  
  "status": "OK",  
  "count": 2,  
  "results": \[  

    {  
      "age": 27,  
      "name": "Oz",  

      "lactose_intolerant": true  
    },  
    {  
      "age": 29,  

      "name": "Joe",  
      "lactose_intolerant": false  
    }  
  \]  

}

for x in range(1,101):  
    print"fizz"\[x%3*len( fizz )::\]+"buzz"\[x%5*len( buzz )::\] or x

print "Hello" if True else "World"  
>>> Hello

nfc = \["Packers", "49ers"\]  
afc = \["Ravens", "Patriots"\]  
print nfc + afc  
>>> \[ Packers ,  49ers ,  Ravens ,  Patriots \]  

print str(1) + " world"  
>>> 1 world  

print \`1\` + " world"  
>>> 1 world  

print 1, "world"  
>>> 1 world  
print nfc, 1  
>>> \[ Packers ,  49ers \] 1

x = 2  
if 3 > x > 1:  
   print x  
>>> 2  
if 1  0:  
   print x  
>>> 2

nfc = \["Packers", "49ers"\]  
afc = \["Ravens", "Patriots"\]  
for teama, teamb in zip(nfc, afc):  
     print teama + " vs. " + teamb  
>>> Packers vs. Ravens  
>>> 49ers vs. Patriots

teams = \["Packers", "49ers", "Ravens", "Patriots"\]  
for index, team in enumerate(teams):  
    print index, team  
>>> 0 Packers  
>>> 1 49ers  
>>> 2 Ravens  
>>> 3 Patriots

numbers = \[1,2,3,4,5,6\]  
even = \[\]  
for number in numbers:  
    if number%2 == 0:  
        even.append(number)

numbers = \[1,2,3,4,5,6\]  
even = \[number for number in numbers if number%2 == 0\]

teams = \["Packers", "49ers", "Ravens", "Patriots"\]  
print {key: value for value, key in enumerate(teams)}  
>>> { 49ers : 1,  Ravens : 2,  Patriots : 3,  Packers : 0}

items = \[0\]*3  
print items  
>>> \[0,0,0\]

teams = \["Packers", "49ers", "Ravens", "Patriots"\]  
print ", ".join(teams)  
>>>  Packers, 49ers, Ravens, Patriots

data = { user : 1,  name :  Max ,  three : 4}  
try:  
   is_admin = data\[ admin \]  
except KeyError:  
   is_admin = False

data = { user : 1,  name :  Max ,  three : 4}  
is_admin = data.get( admin , False)

x = \[1,2,3,4,5,6\]  
#前3个  
print x\[:3\]  
>>> \[1,2,3\]  
#中间4个  
print x\[1:5\]  
>>> \[2,3,4,5\]  
#最后3个  
print x\[3:\]  
>>> \[4,5,6\]  
#奇数项  
print x\[::2\]  
>>> \[1,3,5\]  
#偶数项  
print x\[1::2\]  
>>> \[2,4,6\]

from collections import Counter  
print Counter("hello")  
>>> Counter({ l : 2,  h : 1,  e : 1,  o : 1})

from itertools import combinations  
teams = \["Packers", "49ers", "Ravens", "Patriots"\]  
for game in combinations(teams, 2):  
    print game  
>>> ( Packers ,  49ers )  
>>> ( Packers ,  Ravens )  
>>> ( Packers ,  Patriots )  
>>> ( 49ers ,  Ravens )  
>>> ( 49ers ,  Patriots )  
>>> ( Ravens ,  Patriots )

False = True  
if False:  
   print "Hello"  
else:  
   print "World"  
>>> Hello