python常見內置函數的用法

1.enumerate()：enumerate(sequence, [start=0]) ，sequence是可迭代對象，[start]是起始位置。多用於在for循環中得到計數，可以同時獲得索引和值，即需要index和value值的時候可以使用。

>>> country=["China","America","Korea","Russia","India","Thailand"]
>>> list(enumerate(country))
[(0, 'China'), (1, 'America'), (2, 'Korea'), (3, 'Russia'), (4, 'India'), (5, 'Thailand')]

>>> country=["China","America","Korea","Russia","India","Thailand"]
>>> for each in enumerate(country):
	print(each)	
(0, 'China')
(1, 'America')
(2, 'Korea')
(3, 'Russia')
(4, 'India')
(5, 'Thailand')

>>> for each in enumerate(country,2):
	print(each)
(2, 'China')
(3, 'America')
(4, 'Korea')
(5, 'Russia')
(6, 'India')
(7, 'Thailand')

例：統計文件行數

>>> count = 0
>>> file=open("Largefile.txt","r")
>>> for each in enumerate(file):
	count+=1

>>> count  #實際行數是count+1
804