17 Python tips to share

1. Exchange variables

x = 6

y = 5
x, y = y, x
print x

>>> 5

print y

>>> 6

2. If statement in line

print "Hello" if True else "World"

>>> Hello

3. The connection

This last approach is cool when binding two different types of objects.

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

4. Calculation skills

# Take down the whole 

print 5.0//2

>>> 2

# 2 the 5 To the power 

print 2**5

>> 32

Pay attention to the division of floating point Numbers

print .3/.1

>>> 2.9999999999999996

print .3//.1

>>> 2.0

5. Numerical comparison

x = 2

if 3 > x > 1:

   print x

>>> 2

if 1 < x > 0:

   print x

>>> 2

6. Both lists iterate at the same time

nfc = ["Packers", "49ers"]

afc = ["Ravens", "Patriots"]

for teama, teamb in zip(nfc, afc):

     print teama + " vs. " + teamb

>>> Packers vs. Ravens

>>> 49ers vs. Patriots

7. Iteration of indexed lists

teams = ["Packers", "49ers", "Ravens", "Patriots"]

for index, team in enumerate(teams):

    print index, team

>>> 0 Packers

>>> 1 49ers

>>> 2 Ravens

>>> 3 Patriots

8. List derivation

Given a list, brush to select an even list method:

numbers = [1,2,3,4,5,6]

even = []

for number in numbers:

    if number%2 == 0:

        even.append(number)

Replace it with the following

numbers = [1,2,3,4,5,6]

even = [number for number in numbers if number%2 == 0]

9. Dictionary derivation

teams = ["Packers", "49ers", "Ravens", "Patriots"]

print {key: value for value, key in enumerate(teams)}

>>> {'49ers': 1, 'Ravens': 2, 'Patriots': 3, 'Packers': 0}

Initialize the values of the list

items = [0]*3

print items

>>> [0,0,0]

Convert the list to a string

teams = ["Packers", "49ers", "Ravens", "Patriots"]

print ", ".join(teams)

>>> 'Packers, 49ers, Ravens, Patriots'

Get elements from a dictionary

Don't do it the following way

Data = {'user': 1, 'name': 'Max', 'three': 4}
Try:
    Is_admin = data [' admin ']
Except KeyError:
    Is_admin = False
Replace with

data = {'user': 1, 'name': 'Max', 'three': 4}

is_admin = data.get('admin', False)

13. Get the sublist

x = [1,2,3,4,5,6]

# before 3 a 

print x[:3]

>>> [1,2,3]

# In the middle 4 a 

print x[1:5]

>>> [2,3,4,5]

# The last 3 a 

print x[-3:]

>>> [4,5,6]

# An odd number of items 

print x[::2]

>>> [1,3,5]

# Even term 

print x[1::2]

>>> [2,4,6]

14.60 characters to solve FizzBuzz

Some time ago Jeff Atwood popularized a simple programming exercise called FizzBuzz.

Write a program that prints the Numbers 1 to 100, replace it with "Fizz" in multiples of 3, "Buzz" in multiples of 5, and "FizzBuzz" in multiples of both 3 and 5.
Here's a short solution to this problem:

For the x in the range (101) : print "fizz" [x % 3 * 4: :] + "buzz" [x % 5 * 4: :] or x

Collection of 15.

Library use Counter

from collections import Counter

print Counter("hello")

>>> Counter({'l': 2, 'h': 1, 'e': 1, 'o': 1})

16. Iteration tools

Like the collections library, there is also a library called itertools

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')

17. False = = True

In python, True and False are global variables, so:

False = True

if False:

   print "Hello"

else:

   print "World"

>>> Hello

Above is a personal summary of some commonly used Pyton tips, more suitable for beginners, hope you can like.