readlines() 在 Python 3 中是否返回列表或迭代器?

Does readlines() return a list or an iterator in Python 3?(readlines() 在 Python 3 中是否返回列表或迭代器?)
本文介绍了readlines() 在 Python 3 中是否返回列表或迭代器?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着跟版网的小编来一起学习吧!

问题描述

我读过深入 Python 3".那:

I've read in "Dive into Python 3" that:

readlines() 方法现在返回一个迭代器,因此它与 Python 2 中的 xreadlines() 一样高效".em>

"The readlines() method now returns an iterator, so it is just as efficient as xreadlines() was in Python 2".

参见:附录 A:移植代码使用 2to3 到 Python 3:A.26 xreadlines() I/O 方法.

我不确定这是不是真的,因为他们在这里没有提到:http://docs.python.org/release/3.0.1/whatsnew/3.0.html .如何检查?

I'm not sure that's true because they don't mention it here: http://docs.python.org/release/3.0.1/whatsnew/3.0.html . How can I check that?

推荐答案

像这样:

Python 3.1.2 (r312:79149, Mar 21 2010, 00:41:52) [MSC v.1500 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> f = open('/junk/so/foo.txt')
>>> type(f.readlines())
<class 'list'>
>>> help(f.readlines)
Help on built-in function readlines:

readlines(...)
    Return a list of lines from the stream.

    hint can be specified to control the number of lines read: no more
    lines will be read if the total size (in bytes/characters) of all
    lines so far exceeds hint.

>>>

这篇关于readlines() 在 Python 3 中是否返回列表或迭代器?的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持跟版网!

本站部分内容来源互联网,如果有图片或者内容侵犯了您的权益,请联系我们,我们会在确认后第一时间进行删除!

相关文档推荐

groupby multiple coords along a single dimension in xarray(在xarray中按单个维度的多个坐标分组)
Group by and Sum in Pandas without losing columns(Pandas中的GROUP BY AND SUM不丢失列)
Group by + New Column + Grab value former row based on conditionals(GROUP BY+新列+基于条件的前一行抓取值)
Groupby and interpolate in Pandas(PANDA中的Groupby算法和插值算法)
Pandas - Group Rows based on a column and replace NaN with non-null values(PANAS-基于列对行进行分组,并将NaN替换为非空值)
Grouping pandas DataFrame by 10 minute intervals(按10分钟间隔对 pandas 数据帧进行分组)