关于循环：如何让python只读取包含诗的文件中的每一行

How do I get python to read only every other line from a file that contains a poem

我知道每一行的代码是

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

如何让python从原始文件中只读偶数行。假设以1为基础的行编号。

有很多不同的方法，这里有一个简单的

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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，保存用于声明和增加计数的行：

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