嘗試刪除文本文件中包含特定字符的行

Question

我正在測試下面的代碼，但它沒有做我希望它做的事情。

delete_if = ['#', ' ']
with open('C:\\my_path\\AllDataFinal.txt') as oldfile, open('C:\\my_path\\AllDataFinalFinal.txt', 'w') as newfile:
    for line in oldfile:
        if not any(del_it in line for del_it in delete_if):
            newfile.write(line)
print('DONE!!')

基本上，我想刪除任何包含“#”字符的行（我想刪除的行以“#”字符開頭）。 另外，我想刪除任何/所有完全空白的行。 我可以在旅途中通過閱讀列表中的項目來完成此操作，還是需要多次通過文本文件來清理所有內容？ TIA。

Answer 1

這很簡單。 在下面檢查我的代碼：

filePath = "your old file path"
newFilePath = "your new file path"

# we are going to list down which lines start with "#" or just blank
marker = []

with open(filePath, "r") as file:
    content = file.readlines() # read all lines and store them into list

for i in range(len(content)): # loop into the list
    if content[i][0] == "#" or content[i] == "\n": # check if the line starts with "#" or just blank
        marker.append(i) # store the index into marker list

with open(newFilePath, "a") as file:
    for i in range(len(content)): # loop into the list
        if not i in marker: # if the index is not in marker list, then continue writing into file
            file.writelines(content[i]) # writing lines into file

關鍵是，我們需要先閱讀所有的行。 並逐行檢查它是否以#開頭或只是空白。 如果是，則將其存儲到列表變量中。 之后，我們可以通過檢查該行的索引是否在標記中來繼續寫入新文件。

如果您有問題，請告訴我。

Answer 2

如何使用三元運算符？

 #First option: within your for loop
 line = "" if "#" in line or not line else line

 #Second option: with list comprehension
 newFile = ["" if not line or "#" in line else line for line in oldfile]

我不確定三元是否有效，因為如果字符串為空，則應顯示異常，因為“#”不會在空字符串中......怎么樣

#Third option: "Staging your conditions" within your for loop
#First, make sure the string is not empty
if line:
    #If it has the "#" char in it, delete it
    if "#" in line:
        line = ""
#If it is, delete it
else: 
    line = ""