python与js比少了声明，少了大括号，少了分号，多了必要层级。
#变量
只需要直接赋值就可以，前面不需要任何声明，可以用print(variable)查看变量。例如：
a = 1
b = 'string'
print(a, b) # 1 string
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#If-Else
mark = 65
if mark < 60:
print('你挂了！')
elif mark < 90:
print('你通过了！')
else:
print('你很优秀！')
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#函数
#最简单的形式：
def function1():
print('a')
function1() # a
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#参数形式
def function2(num):
return num ** 2
function2(5) # 25
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#List
等同于其他语言的数组,比如js
a = [1, 'a', True]
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#append——把一项数据添加到数组最后面
类似于js的push
a = [1]
a.append('a')
print(a) # [1, 'a']
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#pop——删除数组最后一项
a = [1, 'a']
a.pop()
print(a) # [1]
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#for循环
b = [20, 10, 5]
total = 0
for e in b:
total += e
print(total)
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#while循环
##############
# total = 0
# for i in range(1, 5):
# total += i
# print(total)
##############
total2 = 0
j = 1
while j < 5:
total2 += j
j += 1
print(total2)
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#dictionary
等同于其它例如js的json
d = { "George": 24, "Tom": 32 }
d["George"] = 25
for key, value in d.items():
print("key:", key)
print("value:", value)
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#class和object
class Robot:
def __init__(self, name, color, weight):
self.name = name
self.color = color
self.weight = weight
def introduce_self(self):
print("My name is " + self.name)
r1 = Robot("Tom", "red", 70)
r1.introduce_self()
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#Boolean
type(True)
type(False)
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#list comprehension
a = [x ** 2 for x in range(6, 0, -1)]
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#set
a = set()
a.add(1)
for x in a:
print(x)
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