# trips/models.py

from django.db import models

class Post(models.Model):
    title = models.CharField(max_length=100)
    content = models.TextField(blank=True)
    photo = models.URLField(blank=True)
    created_at = models.DateTimeField(auto_now_add=True)

單行註解
#This is a comment.    

多行註解
"""This is a
multiline docstring."""    

'''This is a
multiline docstring.'''

this_is_a_number = 1

ThisIsANumber = 1

>>> import keyword

>>> keyword.kwlist

['False', 'None', 'True', 'and', 'as', 'assert', 'break', 'class',
 'continue', 'def', 'del', 'elif', 'else', 'except', 'finally', 'for',
 'from', 'global', 'if', 'import', 'in', 'is', 'lambda', 'nonlocal', 'not',
 'or', 'pass', 'raise', 'return', 'try', 'while', 'with', 'yield']

x = 1        # int
y = 2.8      # float
z = 3+5j     # complex

>>> x=1.23
>>> type(x)
<class 'float'>

>>> x = 5

>>> print(x > 3 and x < 10)

>>> print((x > 10) or (x % 2 == 0))

>>> print(not(x > 3 and x < 10))

x = ["apple", "banana"]
y = ["apple", "banana"]
z = x

print(x is z)    # True because z is the same object as x

print(x is y)    # False because x is not the same object as y, 
                    even if they have thew same content

print(x == y)    # True because x is equal to y

# the difference betweeen "is" and "==": 
    is -> 參考到同一個櫃子
    == -> 內容相同

x = ["apple", "banana"]

print("banana" in x)

# returns True 
because a sequence with the value "banana" is in the list

thislist = ["apple", "banana", "cherry"]
thislist[1] = "blackcurrant"
print(thislist)

thislist = ["apple", "banana", "cherry"]
for x in thislist:
  print(x)

thislist = ["apple", "banana", "cherry"]
thislist.insert(1, "orange")
print(thislist)

thistuple = ("apple", "banana", "cherry")
thistuple[1] = "blackcurrant"

print(thistuple)        
# the value is still the same.

thisset = {"apple", "banana", "cherry"}

thisset.add("orange")    
# add one item

thisset.update(["orange", "mango", "grapes"])    
# add more than one item

thisdict = { "brand": "Ford", "model": "Mustang", "year": 1964 }

x = thisdict["model"]
y = thisdict.get("model")
print(x,y)                # Mustang Mustang

thisdict["year"] = 2018
print(thisdict)

for x, y in thisdict.items():
  print(x, y)

>>> x = 12.63718

>>> int(x)
12

>>> round(x,2)
12.64

>>> round(x,3)
12.637


sum = 1 + 2 + 3 + 4 + \
      5 + 6

sum = 1 + 2 + 3 + 4 + 5 + 6

將 x=1 , y=2 內的值對調

x = 1
y = 2
temp = x
x = y
y = temp

vs.

x, y = y, x

~$ vim test.py


name = input("Please enter your name: ")
print("hello, " + name)


i            進入修改模式
Esc + :wq    儲存後並關閉


~$ python3 test.py    執行

~$ vim test.py    再次修改

this_a_string = " SIRLA "
print(this_a_string + " Enlightened ")
print(this_a_string * 3)

radius = eval(input("Enter a value for radius: "))
area = radius**2 * 3.14

print(area)

radius = eval(input("Enter a value for radius: "))
area = radius**2 * 3.14

print(area)

sudo apt-get install python-pip

import [module_name] as [Custom_name]

import math
print(math.pi)

import math as m     # 為 math 模組取別名為 m
print(m.pi)


from [module_name] import [name1, name2, ... nameN]

from math import pi
print(pi)

from math import pi

radius = eval(input("Enter a value for radius: "))
area = radius**2 * pi

print(area)

from math import pi

radius = eval(input("Enter a value for radius: "))
area = radius**2 * pi

print(area)

hit_value = 800
dodge_value = int(input("Input monster's dodging value: "))

# Input your code here
hit_rate = (hit_value - dodge_value) / 1000 * 100
print("Your hit rate is: " + str(hit_rate) + "%")

hit_value = 800
dodge_value = int(input("Input monster's dodging value: "))

# Input your code here
hit_rate = (hit_value - dodge_value) / 1000 * 100
print("Your hit rate is: " + str(hit_rate) + "%")

import random
random.randint(0, 2)    # 在 0, 1, 2 中取亂數

random.randint(1, 2)    # 在 1, 2 中取亂數

num = int(input("enter your number: "))

if num > 0:
    print("Positive")
elif num == 0:
    print("equal 0")
else: # num < 0
    print("Negative")

import random

girlfriend_probability = random.randint(0, 100)

if girlfriend_probability == -1:
    print("You wil have a girlfriend soon.")
else:
    print("You're on your own.")
    

i = 1
while i < 6:
  print(i)
  if i == 3:
    break
  i += 1 

# 印出 1 2 3

i = 0
while i < 6:
  i += 1
  if i == 3:
    continue
  print(i)

# 印出 1 2 4 5 6

break -> 程式中止,不跑了
continue -> 跳過該段程式,繼續下一個

while True:
    x = str(input())
    x_reverse = x[::-1]
    if x_reverse == x:
        print("YES")
    else:
        print("NO")

while True:
    n = eval(input())
    pi_even = 0
    pi_odd = 0
    
    if n > 0:
        for k in range(3,2*n+1,4):
            pi_even = pi_even - (4/k)
            for p in range(5,2*n+1,4):
                pi_odd = pi_odd + (4/p)
        print(4 + pi_even + pi_odd)
    else:
        print("")