Python.代码在csv文件中的每一行后面都留有空白行

Question

为什么代码不仅删除winningRows，还删除csv标题行，并在每行之后保留空白行？如何修复？我只需要删除winningRows，不需要空白行。

def generate():
global winningRows
filename = enterFile()
noOfWinners = 5
winningNumbers = []
while len(winningNumbers) < noOfWinners:
luckyNumber = random.randint(1, totalEntries)
if luckyNumber not in winningNumbers:
winningNumbers.append(luckyNumber)
with open(filename, newline="") as entriesCSV:
entriesDict = csv.DictReader(entriesCSV,dialect="excel")
allRows = [row for row in entriesDict]
winningRows = [row for row in allRows if int(row["#"]) in winningNumbers]
nonWinningRows = [row for row in allRows if int(row["#"]) not in winningNumbers]
for row in winningRows:
winnerName = row["Name"]
winnerID = row["ID"]
winnerEmail = row["Email"]
print(f"The winner is {winnerName}, ID {winnerID}, email {winnerEmail}")
csv.DictWriter(open(filename, "w"), fieldnames=["#", "Name", "ID", "Email"]).writeheader()
csv.DictWriter(open(filename, "w"), fieldnames=["#", "Name", "ID", "Email"]).writerows(nonWinningRows)

csv，然后运行代码

运行代码后的csv

看起来这是有效的：

with open(filename, newline='n') as entriesCSV:
entriesDict = csv.DictReader(entriesCSV,dialect="excel")
allRows = [row for row in entriesDict]
winningRows = [row for row in allRows if int(row["#"]) in winningNumbers]
nonWinningRows = [row for row in allRows if int(row["#"]) not in winningNumbers]
for row in winningRows:
winnerName = row["Name"]
winnerID = row["ID"]
winnerEmail = row["Email"]
print(f"The winner is {winnerName}, ID {winnerID}, email {winnerEmail}")
with open(filename, "w", newline='n') as entriesCSV:
writer = csv.DictWriter(entriesCSV, fieldnames=["#", "Name", "ID", "Email"])
writer.writeheader()
writer.writerows(nonWinningRows)

但在这种情况下，我会打开两次文件，对吧？

Answer 1

看起来您在Windows上。将newline参数添加到open函数中。

with open(filename, "w", newline='n') as fp:
writer = csv.DictWriter(fp, fieldnames=["#", "Name", "ID", "Email"])
writer.writeheader()
writer.writerows(nonWinningRows)

Answer 2

您正在并行多次打开同一个文件。没有数据我无法测试，但这行得通吗？

with open(filename, newline="") as entriesCSV:
entriesDict = csv.DictReader(entriesCSV,dialect="excel")
allRows = [row for row in entriesDict]
winningRows = [row for row in allRows if int(row["#"]) in winningNumbers]
nonWinningRows = [row for row in allRows if int(row["#"]) not in winningNumbers]
for row in winningRows:
winnerName = row["Name"]
winnerID = row["ID"]
winnerEmail = row["Email"]
print(f"The winner is {winnerName}, ID {winnerID}, email {winnerEmail}")
with open(filename, "w") as outputCSV:
writer = csv.DictWriter(outputCSV, fieldnames=["#", "Name", "ID", "Email"])
writer.writeheader()
writer.writerows(nonWinningRows)