For 循环 - 我只能输入 1 个整数

Question

我无法输入一个以上的整数。我应该能够指定多少，然后像这样输入...

How many integers? 3
Please enter an integer 1: 5
Please enter an integer 2: 2
Please enter an integer 3: 6
Using a for loop
5
2
6

但是我只被要求输入整数 1（在连续循环中）

代码如下：-

#!/usr/bin/env python2

import sys

target_int = raw_input("How many integers?")

try:
  target_int = int(target_int)
except ValueError:
  sys.exit("You must enter an integer")

ints = list()

count = 0

while count < target_int:
 new_int = raw_input("Please enter integer {0}:".format(count + 1))
 isint = False
 try:
   new_int = int(new_int)

 except:
   print("You must enter an integer")

 if isint == True:
     ints.append(new_int)
     count += 1

print("Using a for loop")
for value in ints:
  print(str(value))
~

Answer 1

您的主要问题如前所述，您没有设置 isint。但是无论如何您都不应该，因为您已经在 try 块中进行了投射。所以如果你到达这个代码，它必然是一个int。 2其他小东西是，我是运行在Python 3，因为是14年前发布的，所以raw_input是input，好进使用 [] 而不是 list() 初始化列表的习惯。它有时更快，永远不会更慢。

这是工作代码：

import sys

target_int = input("How many integers?")

try:
    target_int = int(target_int)
except ValueError:
    sys.exit("You must enter an integer")

ints = []

count = 0

while count < target_int:
    new_int = input("Please enter integer {0}:".format(count + 1))
    try:
        new_int = int(new_int)
    except ValueError:
        print("You must enter an integer")
        continue # so it doesn't try to append

    # No need to check isint. It is.
    ints.append(new_int)
    count += 1

print("Using a for loop")
for value in ints:
    print(str(value))

另一个小的改进是完全避免 count，因为它总是已经是 ints 的长度。

import sys

target_int = input("How many integers?")

try:
    target_int = int(target_int)
except ValueError:
    sys.exit("You must enter an integer")

ints = []

while len(ints) < target_int:
    new_int = input("Please enter integer {0}:".format(len(ints) + 1))
    try:
        ints.append(int(new_int))
    except ValueError:
        print("You must enter an integer")


print("Using a for loop")
for value in ints:
    print(str(value))

For 循环 - 我只能输入 1 个整数

For loop - I can only enter 1 integer

python

integer

for-loop

python-2.x