将字符串附加到python中.txt文件的每一行？

Question

我想在文件的每一行附加一些文本

这是我的代码

filepath = 'hole.txt'
with open(filepath) as fp:
    line = fp.readline()
    cnt = 1
    while line:
        #..........
        #want to append text "#" in every line by reading line by line 
        text from .txt file
        line = fp.readline()
        cnt += 1

Answer 1

您可以阅读这些行并将它们放在一个列表中。 然后使用写入模式打开相同的文件，并使用要追加的字符串写入每一行。

filepath = "hole.txt"
with open(filepath) as fp:
    lines = fp.read().splitlines()
with open(filepath, "w") as fp:
    for line in lines:
        print(line + "#", file=fp)

Answer 2

假设您可以在内存中加载全文，您可以逐行打开文件，并为每一行添加“＃”。 然后保存:-)：

with open(filepath, 'r') as f:     # load file
    lines = f.read().splitlines()  # read lines

with open('new_file.txt', 'w') as f: 
    f.write('\n'.join([line + '#' for line in lines]))  # write lines with '#' appended

Answer 3

我假设文件足够小，可以在内存中保留两份副本：

filepath = 'hole.txt'
with open(filepath, 'r') as f:
    original_lines = f.readlines()

new_lines = [line.strip() + "#\n" for line in original_lines]

with open(filepath, 'w') as f:
    f.writelines(new_lines)

首先，我们打开文件并将所有行读入列表。 然后，通过strip()从每一行中的行终止符生成一个新列表，在其后添加一些额外的文本和一个新的行终止符。

然后，最后一行用新的修改行覆盖文件。

Answer 4

这有帮助吗？

inputFile = "path-to-input-file/a.txt"
outputFile = "path-to-output-file/b.txt"
stringToAPpend = "#"

with open(inputFile, 'r') as inFile, open(outputFile, 'w') as outFile:
    for line in inFile:
        outFile.write(stringToAPpend+line)