打印第3行，

line_number = 3

with open(filename,"r") as file:
current_line = 1
for line in file:
    if current_line == line_number:
        print(file.readline())
        break
    current_line += 1

原作者:Frank Hofmann

with open("test.txt", "r") as fp:
   lines = fp.readlines()
print(lines[3])

Test.txt是文件名 打印test.txt中的第4行

def getitems(iterable, items):
  items = list(items) # get a list from any iterable and make our own copy
                      # since we modify it
  if items:
    items.sort()
    for n, v in enumerate(iterable):
      if n == items[0]:
        yield v
        items.pop(0)
        if not items:
          break

print list(getitems(open("/usr/share/dict/words"), [25, 29]))
# ['Abelson\n', 'Abernathy\n']
# note that index 25 is the 26th item

打印所需的行。 打印行在所需行位的上方/下方。

def dline(file,no,add_sub=0):
    tf=open(file)
    for sno,line in enumerate(tf):
        if sno==no-1+add_sub:
         print(line)
    tf.close()

执行---->dline("D:\dummy.txt"，6)即dline("文件路径"，line_number，如果你想要搜索行的上行给出1为低-1这是可选的默认值将采取0)

文件对象有一个.readlines()方法，它将为您提供文件内容的列表，每个列表项一行。在此之后，您可以使用普通的列表切片技术。

http://docs.python.org/library/stdtypes.html#file.readlines

这是我的2美分，不管它是否值得;)

def indexLines(filename, lines=[2,4,6,8,10,12,3,5,7,1]):
    fp   = open(filename, "r")
    src  = fp.readlines()
    data = [(index, line) for index, line in enumerate(src) if index in lines]
    fp.close()
    return data


# Usage below
filename = "C:\\Your\\Path\\And\\Filename.txt"
for line in indexLines(filename): # using default list, specify your own list of lines otherwise
    print "Line: %s\nData: %s\n" % (line[0], line[1])