如何让python只从包含一首诗的文件中读取每隔一行

Question

我知道读取每一行的代码是

f=open ('poem.txt','r')
for line in f: 
    print line 

如何让python只从原始文件中读取偶数行。假设行号为1

Answer 1

有很多不同的方法，这里有一个简单的

with open('poem.txt', 'r') as f:
    count = 0
    for line in f:
        count+=1
        if count % 2 == 0: #this is the remainder operator
            print(line)

这也可能更好一点，节省了声明和增加计数的行:

with open('poem.txt', 'r') as f:
    for count, line in enumerate(f, start=1):
        if count % 2 == 0:
            print(line)

Answer 2

摘自Nick Bastin的评论:

with open('poem.txt', 'r') as f:
    for count, line in enumerate(f, start=1):
        if count % 2 == 0:
            print line