Python AttributeError: 'int' 对象没有属性 'isdigit'
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AttributeError: 'int' object has no attribute 'isdigit'
提问by Kristofer Ard
numOfYears = 0
cpi = eval(input("Enter the CPI for July 2015: "))
if cpi.isdigit():
while cpi < (cpi * 2):
cpi *= 1.025
numOfYears += 1
print("Consumer prices will double in " + str(numOfYears) + " years.")
while not cpi.isdigit():
print("Bad input")
cpi = input("Enter the CPI for July 2015: ")
I'm getting the following error.
我收到以下错误。
AttributeError: 'int' object has no attribute 'isdigit'
AttributeError: 'int' 对象没有属性 'isdigit'
Since I'm new to programming, I don't really know what it's trying to tell me. I'm using the if cpi.isdigit():to check to see if what the user entered is a valid number.
由于我是编程新手，我真的不知道它想告诉我什么。我正在使用if cpi.isdigit():来检查用户输入的数字是否有效。
采纳答案by Ben
numOfYears = 0
# since it's just suppposed to be a number, don't use eval!
# It's a security risk
# Simply cast it to a string
cpi = str(input("Enter the CPI for July 2015: "))
# keep going until you know it's a digit
while not cpi.isdigit():
print("Bad input")
cpi = input("Enter the CPI for July 2015: ")
# now that you know it's a digit, make it a float
cpi = float(cpi)
while cpi < (cpi * 2):
cpi *= 1.025
numOfYears += 1
# it's also easier to format the string
print("Consumer prices will double in {} years.".format(numOfYears))
回答by marmeladze
As documented hereisdigit()is a string method. You can't call this method for integers.
正如这里记录的那样，isdigit()是一个字符串方法。您不能为整数调用此方法。
This line,
这条线，
cpi = eval(input("Enter the CPI for July 2015: "))
evaluatesthe user input to integer.
evaluates用户输入为整数。
>>> x = eval(input("something: "))
something: 34
>>> type(x)
<class 'int'>
>>> x.isdigit()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AttributeError: 'int' object has no attribute 'isdigit'
But if you remove evalmethod (you should better do that),
但是如果你删除eval方法（你最好这样做），
>>> x = input("something: ")
something: 54
>>> type(x)
<class 'str'>
>>> x.isdigit()
True
everything will be fine.
一切都会好起来的。
by the way using eval without sanitizin user input may cause problems
顺便说一下，在没有 sanitizin 用户输入的情况下使用 eval 可能会导致问题
consider this.
考虑这个。
>>> x = eval(input("something: "))
something: __import__('os').listdir()
>>> x
['az.php', 'so', 'form.php', '.htaccess', 'action.php' ...
回答by Kevin Guan
eval()is very dangerous!And int()built-in function can convert string to digit.
eval()很危险！并且int()内置函数可以将字符串转换为数字。
If you want to catch the error if user didn't enter a number, just use try...exceptlike this:
如果你想在用户没有输入数字的情况下捕获错误，只需try...except像这样使用：
numOfYears = 0
while numOfYears == 0:
try:
cpi = int(input("Enter the CPI for July 2015: "))
except ValueError:
print("Bad input")
else:
while cpi < (cpi * 2):
cpi *= 1.025
numOfYears += 1
print("Consumer prices will double in", numOfYears, "years.")
回答by usr_11
Use this:
用这个：
if(str(yourvariable).isdigit()) :
print "number"
isdigit()works only for strings.
isdigit()仅适用于字符串。
