將數字寫入文件python。 第一次輸入不打印

Question

我正在將數字寫入文本文件，它可以工作，但即時通訊存在的問題是它不打印第一個數字。

如果我寫1 2 3 4 5 6，那么我有一個哨兵循環，並使用-1結束。

它會打印2 3 4 5 6

outfile = open("userInput.txt","w")
userInput = int(input("Enter a number to the text file: "))
count = 0
if int(userInput) != -1:
   while(userInput) !=-1:
       userInput = int(input("Enter a number to the text file: "))
       outfile.write(str(userInput) + "\n")
       count+=1
if count == 0:
   print("There is no numbers in the text file")
   outfile.write("There is no numbers in the text file")
count+=1
outfile.close()

Answer 1

在將第一個輸入寫入文件之前，您是在第二次提示用戶。

參見此處：（我也簡化了您的代碼）

outfile = open("userInput.txt","w")
userInput = int(input("Enter a number to the text file: "))
count = 0
while(userInput !=-1): # You don't need the if, because if userInput == -1, this while loop won't run at all
   outfile.write(str(userInput) + "\n") # Swapped these lines so that it would write before asking the user again
   userInput = int(input("Enter a number to the text file: "))
   count+=1
if count == 0:
   print("There is no numbers in the text file")
   outfile.write("There is no numbers in the text file")
outfile.close()

Answer 2

您需要新的輸入並在將第一個有效輸入寫入文件之前將其寫入。 相反，請先輸入有效輸入，然后再要求輸入。

outfile = open("userInput.txt","w")
userInput = int(input("Enter a number to the text file: "))
count = 0
while(userInput != -1)
    outfile.write(str(userInput) + "\n")
    userInput = int(input("Enter a number to the text file: "))
    count+=1
if count == 0:
   print("There is no numbers in the text file")
   outfile.write("There is no numbers in the text file")
outfile.close()

這應該工作。