我如何写一个列表文件?writelines()不插入换行符,所以我需要这样做:
f.writelines([f"{line}\n" for line in lines])
我如何写一个列表文件?writelines()不插入换行符,所以我需要这样做:
f.writelines([f"{line}\n" for line in lines])
当前回答
poem = '''\
Programming is fun
When the work is done
if you wanna make your work also fun:
use Python!
'''
f = open('poem.txt', 'w') # open for 'w'riting
f.write(poem) # write text to file
f.close() # close the file
How It Works: First, open a file by using the built-in open function and specifying the name of the file and the mode in which we want to open the file. The mode can be a read mode (’r’), write mode (’w’) or append mode (’a’). We can also specify whether we are reading, writing, or appending in text mode (’t’) or binary mode (’b’). There are actually many more modes available and help(open) will give you more details about them. By default, open() considers the file to be a ’t’ext file and opens it in ’r’ead mode. In our example, we first open the file in write text mode and use the write method of the file object to write to the file and then we finally close the file.
上面的例子来自Swaroop C H编写的《A Byte of Python》一书。 swaroopch.com
其他回答
这个逻辑首先将list中的项转换为字符串(str)。有时列表包含一个元组,如
alist = [(i12,tiger),
(113,lion)]
这个逻辑将把每个元组写入一个新行。我们可以在读取文件时加载每个元组时使用eval:
outfile = open('outfile.txt', 'w') # open a file in write mode
for item in list_to_persistence: # iterate over the list items
outfile.write(str(item) + '\n') # write to the file
outfile.close() # close the file
使用循环:
with open('your_file.txt', 'w') as f:
for line in lines:
f.write(f"{line}\n")
对于Python <3.6:
with open('your_file.txt', 'w') as f:
for line in lines:
f.write("%s\n" % line)
对于Python 2,还可以使用:
with open('your_file.txt', 'w') as f:
for line in lines:
print >> f, line
如果您热衷于单个函数调用,至少要删除方括号[],以便每次生成一个要打印的字符串(genexp而不是listcomp)——没有理由占用物化整个字符串列表所需的所有内存。
在一般情况下
下面是writelines()方法的语法
fileObject.writelines( sequence )
例子
#!/usr/bin/python
# Open a file
fo = open("foo.txt", "rw+")
seq = ["This is 6th line\n", "This is 7th line"]
# Write sequence of lines at the end of the file.
line = fo.writelines( seq )
# Close opend file
fo.close()
参考
http://www.tutorialspoint.com/python/file_writelines.htm
我建议这个解决方案。
with open('your_file.txt', 'w') as f:
list(map(lambda item : f.write("%s\n" % item),my_list))
我最近发现Path很有用。帮助我绕过不得不打开('file')作为f,然后写入文件。希望这对某些人有用:)。
from pathlib import Path
import json
a = [[1,2,3],[4,5,6]]
# write
Path("file.json").write_text(json.dumps(a))
# read
json.loads(Path("file.json").read_text())