如何遍歷數組數組中的鍵？

Question

我有一個數組，說：

products = [['product_1','description 1'],['product_2','description 2']] 

我要檢查輸入對鍵，e.g，：

product = raw_input('Enter product: ') 
if product not in products.keys(): 
    log.fatal('Invalid product: {}'.format(product)) 
    exit(1) 

keys()不工作 - 我應該怎樣做？

Answer 1

名單不要有鑰匙......你只是希望每個子列表的第一個元素

dict(products).keys() #ONLY if there is exactly 2 items per sublist 

或

zip(*products)[0] #any number of items per sublist is ok 

或

[k for k,val in products] # only if you have EXACTLY 2 items per sublist 

或

[item[0] for item in products] # any number of items in each sublist 

Answer 2

keys不是list的方法。你一定在想着dict。只要做：

products = {k: v for k, v in [['product_1','description 1'],['product_2','description 2']]}