[英]Deleting a specific number of lines from text file using Python
假設我有一個像這樣的文本文件:
AAAAAAAAAAAAAAAAAAAAA #<--- line 1
BBBBBBBBBBBBBBBBBBBBB #<--- line 2
CCCCCCCCCCCCCCCCCCCCC #<--- line 3
DDDDDDDDDDDDDDDDDDDDD #<--- line 4
EEEEEEEEEEEEEEEEEEEEE #<--- line 5
FFFFFFFFFFFFFFFFFFFFF #<--- line 6
GGGGGGGGGGGGGGGGGGGGG #<--- line 7
HHHHHHHHHHHHHHHHHHHHH #<--- line 8
忽略“#<--- line...”,只是為了演示
假設
最終結果
最終結果應如下所示:
CCCCCCCCCCCCCCCCCCCCC #<--- line 3
DDDDDDDDDDDDDDDDDDDDD #<--- line 4
EEEEEEEEEEEEEEEEEEEEE #<--- line 5
刪除的行:前 2 + 下 3 行之后的所有內容(即第 5 行之后)
必需的
歡迎所有 Pythonic 建議! 謝謝!
參考資料
https://thispointer.com/python-how-to-delete-specific-lines-in-a-file-in-a-memory-efficient-way/
def delete_multiple_lines(original_file, line_numbers):
"""In a file, delete the lines at line number in given list"""
is_skipped = False
counter = 0
# Create name of dummy / temporary file
dummy_file = original_file + '.bak'
# Open original file in read only mode and dummy file in write mode
with open(original_file, 'r') as read_obj, open(dummy_file, 'w') as write_obj:
# Line by line copy data from original file to dummy file
for line in read_obj:
# If current line number exist in list then skip copying that line
if counter not in line_numbers:
write_obj.write(line)
else:
is_skipped = True
counter += 1
# If any line is skipped then rename dummy file as original file
if is_skipped:
os.remove(original_file)
os.rename(dummy_file, original_file)
else:
os.remove(dummy_file)
然后...
delete_multiple_lines('sample.txt', [0,1,2])
這種方法的問題可能在於,如果您的文件頂部有 1-100 行要刪除,則您必須指定 [0,1,2...100]。 對?
回答
由@sandes 提供
以下代碼將:
with open("sample.txt", "r") as f:
lines = f.readlines()
new_lines = []
idx_lines_wanted = [x for x in range(63,((63*2)+95))]
# delete first 63, then get the next 95
for i, line in enumerate(lines):
if i > len(idx_lines_wanted) -1:
break
if i in idx_lines_wanted:
new_lines.append(line)
with open("sample2.txt", "w") as f:
for line in new_lines:
f.write(line)
編輯:直接迭代 f
基於@Kenny 的評論和@chepner 的建議
with open("your_file.txt", "r") as f:
new_lines = []
for idx, line in enumerate(f):
if idx in [x for x in range(2,5)]: #[2,3,4]
new_lines.append(line)
with open("your_new_file.txt", "w") as f:
for line in new_lines:
f.write(line)
這確實是由實際的文本編輯器更好地處理的事情。
import subprocess
subprocess.run(['ed', original_file], input=b'1,2d\n+3,$d\nwq\n')
ed
的速成課程,POSIX 標准文本編輯器。
ed
打開以其參數命名的文件。 然后它繼續從其標准輸入讀取命令。 每個命令都是一個字符,有些命令使用一兩個“地址”來指示要操作的行。
在每個命令之后,“當前”行號被設置為最后受命令影響的行。 這與相對地址一起使用,我們稍后會看到。
1,2d
表示刪除第 1 行到第 2 行; 當前行設置為 2+3,$d
刪除從第 5 行(當前行為 2,所以 2 + 3 == 5)到文件末尾的所有行( $
是一個特殊地址,表示文件的最后一行)wq
將所有更改寫入磁盤並退出編輯器。
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.