Python 到 Javascript

zhouer

遍历
python中的for循环很方便，但js中等价的写法 不是 for/in，for/in 语句循环遍历对象的属性：如要遍历打印数组的元素js用forEach
python：
>>> a = [1,2,3,4]
>>> for n in a:
             print n
 
javascript：
a = [1,2,3,4]
a.forEach(function(n){
    alert(n)
})
 
闭包
 

# python 闭包就好像只有一个方法的类
>>> def sandwich_maker(magic_ingredient):
def make(filling):
return magic_ingredient + ' and ' + filling
return make
>>> ham_and = sandwich_maker('ham')
>>> ham_and('cheese')
'ham and cheese'
>>> ham_and('mustard')
'ham and mustard'
>>> turkey_and = sandwich_maker('turkey')
>>> turkey_and('swiss')
'turkey and swiss'
>>> turkey_and('provolone')
'turkey and provolone'
 

function sandwichMaker(ingredient){
function make(filling){
return ingredient + ' and ' + filling;
}
return make
}
var hamAnd = sandwichMaker('ham')
hamAnd('cheese')
"ham and cheese"
hamAnd('mustard')
"ham and mustard"
var turkeyAnd = sandwichMaker('turkey');
turkeyAnd('swiss')
"turkey and swiss"
turkeyAnd('Provolone')
"turkey and Provolone"
 

但是在python中我觉得完全可以用类来写，看着更习惯吧，在js中函数就是类，在python中这样想也好理解
 

>>> class SandwichMaker():
def __init__(self, magic_ingredient):
self.magic_ingredient = magic_ingredient
def make(self, filling):
return self.magic_ingredient + ' and ' + filling
def make2(self, filling):
return self.magic_ingredient + ' and ' + filling
>>> ham_and = SandwichMaker('ham')
>>> ham_and.make('cheese')
'ham and cheese'
>>> ham_and.make('mustard')
'ham and mustard'
>>> turkey_and = SandwichMaker('turkey')
>>> turkey_and.make('swiss')
'turkey and swiss'
>>> turkey_and.make('provolone')
'turkey and provolone'
# 把类改成函数是不是很像，但方法多了调用起来麻烦，所以类就是一个改造过的函数
>>> def SandwichMaker(magic_ingredient):
magic_ingredient = magic_ingredient
def make(filling):
return magic_ingredient + ' and ' + filling
def make2(filling):
return magic_ingredient + ' and ' + filling
return make, make2
>>> ham_and = SandwichMaker('ham')
>>> ham_and[0]('cheese')
'ham and cheese'
>>> ham_and[0]('mustard')
'ham and mustard'
>>> turkey_and = SandwichMaker('turkey')
>>> turkey_and[0]('swiss')
'turkey and swiss'
>>> turkey_and[0]('provolone')
'turkey and provolone'
>>>