eval SyntaxError：python 中的语法无效
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eval SyntaxError: invalid syntax in python
提问by coder_view
I want to assign :
我想分配：
x0='123'
x1='123'
x2='123'
x3='123'
x4='123'
x5='123'
x6='123'
x7='123'
x8='123'
x9='123'
I write the code to express that i can get the output of a string 123when input x1or x8.
我写代码是为了表示我可以123在输入x1或x8.
for i in range(0,10):
eval("x"+str(i)+"='123'")
Traceback (most recent call last):
File "<stdin>", line 2, in <module>
File "<string>", line 1
x0='123'
^
SyntaxError: invalid syntax
How i can do that way?
我怎么能这样做？
采纳答案by suhailvs
For dynamic execution of statements use execstatement.
对于语句的动态执行使用exec语句。
>>> exec('y=3')
>>> y
3
Eval Usgae:eval(expression)
埃瓦尔·乌斯盖：eval(expression)
The expressionargument is parsed and evaluated as a Python expression
该expression参数被解析和评价为Python表达式
eg:
例如：
>>> s=3
>>> eval('s==3')
True
>>> eval('s + 1')
4
>>> eval('s')
3
>>> eval('str(s)+"test"')
'3test'
回答by Martijn Pieters
eval()only allows for expressions. Assignment is not an expression but a statement; you'd have to use execinstead.
eval()只允许表达式。赋值不是表达式而是语句；你必须exec改用。
Even then you could use the globals()dictionary to add names to the global namespace and you'd not need to use any arbitrary expression execution.
即使这样，您也可以使用globals()字典将名称添加到全局命名空间，并且您不需要使用任何任意表达式执行。
You reallydon't want to do this, you need to keep data out of your variable namesand use a list or dictionary instead:
您真的不想这样做，您需要将数据保留在变量名称之外，而是使用列表或字典：
x = ['123'] * 10
would give you a list you can address as x[0], x[1], etc. without having to execute arbitrary expressions.
会给你一个列表，你可以作为解决x[0]，x[1]等等，而无需执行任意表达式。
回答by user3164787
You can you this expression.
你可以你这个表情。
eval('"x"+str(i)+"="+"123"')
