有一个简单的方法来获取前10行:

with open('fileName.txt', mode = 'r') as file:
    list = [line.rstrip('\n') for line in file][:10]
    print(list)

fname = input("Enter file name: ")
num_lines = 0

with open(fname, 'r') as f: #lines count
    for line in f:
        num_lines += 1

num_lines_input = int (input("Enter line numbers: "))

if num_lines_input <= num_lines:
    f = open(fname, "r")
    for x in range(num_lines_input):
        a = f.readline()
        print(a)

else:
    f = open(fname, "r")
    for x in range(num_lines_input):
        a = f.readline()
        print(a)
        print("Don't have", num_lines_input, " lines print as much as you can")


print("Total lines in the text",num_lines)

最直观的两种方法是:

逐行迭代文件，并在N行之后进行换行。 使用next()方法逐行迭代文件N次。(这本质上只是顶部答案的不同语法。)

代码如下:

# Method 1:
with open("fileName", "r") as f:
    counter = 0
    for line in f:
        print line
        counter += 1
        if counter == N: break

# Method 2:
with open("fileName", "r") as f:
    for i in xrange(N):
        line = f.next()
        print line

底线是，只要不使用readlines()或将整个文件枚举到内存中，您就有很多选择。

这里有另一个不错的解决方案与列表理解:

file = open('file.txt', 'r')

lines = [next(file) for x in range(3)]  # first 3 lines will be in this list

file.close()

N = 10
with open("file.txt", "a") as file:  # the a opens it in append mode
    for i in range(N):
        line = next(file).strip()
        print(line)

如果你想要一些明显(不需要在手册中查找深奥的东西)不需要导入就可以工作的东西，请尝试/except，并且可以在相当大范围的Python 2上工作。X版本(2.2至2.6):

def headn(file_name, n):
    """Like *x head -N command"""
    result = []
    nlines = 0
    assert n >= 1
    for line in open(file_name):
        result.append(line)
        nlines += 1
        if nlines >= n:
            break
    return result

if __name__ == "__main__":
    import sys
    rval = headn(sys.argv[1], int(sys.argv[2]))
    print rval
    print len(rval)