如何在 python 2.7 中检查原始输入是否为整数？
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How do I check if raw input is integer in python 2.7?
提问by Alejandro Veintimilla
Is there a method that I can use to check if a raw_inputis an integer?
有没有一种方法可以用来检查 araw_input是否为整数？
I found this method after researching in the web:
我在网上研究后发现了这个方法：
print isinstance(raw_input("number: ")), int)
but when I run it and input 4for example, I get FALSE.
I'm kind of new to python, any help would be appreciated.
但是当我运行它并输入4例如时，我得到FALSE. 我对 python 有点陌生，任何帮助将不胜感激。
采纳答案by falsetru
isinstance(raw_input("number: ")), int)always yields Falsebecause raw_inputreturn string object as a result.
isinstance(raw_input("number: ")), int)总是产生，False因为结果raw_input返回字符串对象。
Use try: int(...) ... except ValueError:
使用try: int(...) ... except ValueError：
number = raw_input("number: ")
try:
int(number)
except ValueError:
print False
else:
print True
or use str.isdigit:
或使用str.isdigit：
print raw_input("number: ").isdigit()
NOTEThe second one yields Falsefor -4because it contains non-digits character. Use the second one if you want digits only.
注意第二个产生Falsefor-4因为它包含非数字字符。如果您只想要数字，请使用第二个。
UPDATEAs J.F. Sebastian pointed out, str.isdigitis locale-dependent (Windows). It might return Trueeven int()would raise ValueError for the input.
更新正如 JF Sebastian 指出的那样，str.isdigit是依赖于语言环境的（Windows）。它可能会返回True甚至int()会为输入引发 ValueError。
>>> import locale
>>> locale.getpreferredencoding()
'cp1252'
>>> '\xb2'.isdigit() # SUPERSCRIPT TWO
False
>>> locale.setlocale(locale.LC_ALL, 'Danish')
'Danish_Denmark.1252'
>>> '\xb2'.isdigit()
True
>>> int('\xb2')
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ValueError: invalid literal for int() with base 10: '\xb2'
回答by Dietrich Epp
You can do it this way:
你可以这样做：
try:
val = int(raw_input("number: "))
except ValueError:
# not an integer
回答by user5322265
here is my solution
这是我的解决方案
`x =raw_input('Enter a number or a word: ')
y = x.isdigit()
if (y == False):
for i in range(len(x)):
print('I'),
else:
for i in range(int(x)):
print('I'),
`
`
回答by Frank Musteman
def checker():
inputt = raw_input("how many u want to check?")
try:
return int(inputt)
except ValueError:
print "Error!, pls enter int!"
return checker()
回答by Elf Machine
Try this method .isdigit(), see example below.
试试这个方法 .isdigit()，见下面的例子。
user_input = raw_input()
if user_input.isdigit():
print "That is a number."
else:
print "That is not a number."
If you require the input to remain digit for further use, you can add something like:
如果您需要输入保持数字以供进一步使用，您可以添加如下内容：
new_variable = int(user_input)
