Python ValueError: 无法将字符串转换为浮点数：'.'
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ValueError: could not convert string to float: '.'
提问by Leo
I have a list of strings (CD_cent) like this:
我有一个像这样的字符串列表（CD_cent）：
2.374 2.559 1.204
and I want to multiply these numbers with a float number. For this I try to convert the list of strings to a list of floats for example with:
我想将这些数字与浮点数相乘。为此，我尝试将字符串列表转换为浮点数列表，例如：
CD_cent2=[float(x) for x in CD_cent]
But I always get the error: ValueError: could not convert string to float: '.'. I guess this means, that it can't convert the dot to a float (?!) But how could I fix this? Why doesn't it recognize the dot?
但我总是收到错误：ValueError: could not convert string to float: '.'. 我想这意味着它无法将点转换为浮点数（？！）但是我该如何解决这个问题？为什么它不识别点？
采纳答案by pythad
You need to spliteach string as the string has multiple values:
您需要split每个字符串，因为字符串有多个值：
your_str = "2.374 2.559 1.204"
floats = [float(x) for x in your_str.split(' ')]
Having a list you can do something like this:
拥有一个列表，您可以执行以下操作：
li = [...]
floats = []
for s in li:
floats.extend([float(x) for x in s.split(' ')])
In your exact situation you have a single string CD_cent = 2.374 2.559 1.204, so you can just:
在您的确切情况下，您只有一个 string CD_cent = 2.374 2.559 1.204，因此您可以：
floats = [float(x) for x in CD_cent.split(' ')]
回答by Ofer Sadan
When I ran your line with the provided data everything worked fine and all the strings converted to floats without error. The error indicates that somewhere in your CD_centthere is a single DOT .that really can't be converted to float.
当我使用提供的数据运行您的行时，一切正常，所有字符串都转换为浮点数而没有错误。该错误表明您的某处CD_cent有一个.确实无法转换为浮动的DOT 。
To try to solve this do:
要尝试解决此问题，请执行以下操作：
CD_cent2=[float(x) for x in CD_cent if x != '.']
And if that doesn't work because of other strings you will have to try...exceptlike this:
如果由于其他字符串而不起作用，您将不得不try...except喜欢这个：
CD_cent2 = []
for x in CD_cent:
try:
CD_cent2.append(float(x))
except ValueError:
pass
All of that is because I assume CD_centis not just a long string like '2.374 2.559 1.204'but it is a list like [2.374,2.559,1.204]. If that is not the case than you should splitthe line like this
所有这一切都是因为我认为CD_cent它不仅仅是一个长字符串，'2.374 2.559 1.204'而是一个像[2.374,2.559,1.204]. 如果情况并非如此，那么您应该split像这样
CD_cent2=[float(x) for x in CD_cent.split()]
