blocks|key|1370270|text|我只会用..。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1370271|try:
++++float(element)
except+ValueError:
++++print+"Not+a+float"|code-block|syntax|javascript|1370272|..这很简单，而且很管用。请注意，如果元素是1<<1024，它仍然会抛出OverflowError。|1370273|另一种选择是正则表达式：|1370274|import+re
if+re.match(r'%5E-?\d%2B(?:\.\d%2B)$',+element)+is+None:
++++print+"Not+float"|1370275|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|D|7|S|8|@]|9|@]|A|$E|F]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

I would just use..
<pre><code>try:
 float(element)
except ValueError:
 print &quot;Not a float&quot;
</code></pre>
..it's simple, and it works. Note that it will still throw OverflowError if element is e.g. 1&lt;&lt;1024.
Another option would be a regular expression:
<pre><code>import re
if re.match(r'^-?\d+(?:\.\d+)$', element) is None:
 print &quot;Not float&quot;
</code></pre>

blocks|key|1370305|text|此正则表达式将检查科学浮点数：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1370306|%5E[-%2B]?(?:\b[0-9]%2B(?:\.[0-9]*)?%7C\.[0-9]%2B\b)(?:[eE][-%2B]?[0-9]%2B\b)?$|code-block|syntax|javascript|1370307|然而，我相信你最好的选择就是尝试使用解析器。|1370308|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

This regex will check for scientific floating point numbers:

<pre><code>^[-+]?(?:\b[0-9]+(?:\.[0-9]*)?|\.[0-9]+\b)(?:[eE][-+]?[0-9]+\b)?$
</code></pre>

However, I believe that your best bet is to use the parser in a try.

blocks|key|1370335|text|用于检查浮动的Python方法：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1370336|def+is_float(element:+Any)+->+bool:
++++try:
++++++++float(element)
++++++++return+True
++++except+ValueError:
++++++++return+False|code-block|syntax|javascript|1370337|始终进行单元测试。什么是浮点，什么不是浮点可能会让你大吃一惊：|1370338|Command+to+parse++++++++++++++++++++++++Is+it+a+float?++Comment
--------------------------------------++---------------+------------
print(isfloat(""))++++++++++++++++++++++False
print(isfloat("1234567"))+++++++++++++++True+
print(isfloat("NaN"))+++++++++++++++++++True++++++++++++nan+is+also+float
print(isfloat("NaNananana+BATMAN"))+++++False
print(isfloat("123.456"))+++++++++++++++True
print(isfloat("123.E4"))++++++++++++++++True
print(isfloat(".1"))++++++++++++++++++++True
print(isfloat("1,234"))+++++++++++++++++False
print(isfloat("NULL"))++++++++++++++++++False+++++++++++case+insensitive
print(isfloat(",1"))++++++++++++++++++++False+++++++++++
print(isfloat("123.EE4"))+++++++++++++++False+++++++++++
print(isfloat("6.523537535629999e-07"))+True
print(isfloat("6e777777"))++++++++++++++True++++++++++++This+is+same+as+Inf
print(isfloat("-iNF"))++++++++++++++++++True
print(isfloat("1.797693e%2B308"))+++++++++True
print(isfloat("infinity"))++++++++++++++True
print(isfloat("infinity+and+BEYOND"))+++False
print(isfloat("12.34.56"))++++++++++++++False+++++++++++Two+dots+not+allowed.
print(isfloat("#56"))+++++++++++++++++++False
print(isfloat("56%25"))+++++++++++++++++++False
print(isfloat("0E0"))+++++++++++++++++++True
print(isfloat("x86E0"))+++++++++++++++++False
print(isfloat("86-5"))++++++++++++++++++False
print(isfloat("True"))++++++++++++++++++False+++++++++++Boolean+is+not+a+float.+++
print(isfloat(True))++++++++++++++++++++True++++++++++++Boolean+is+a+float
print(isfloat("%2B1e1%5E5"))++++++++++++++++False
print(isfloat("%2B1e1"))++++++++++++++++++True
print(isfloat("%2B1e1.3"))++++++++++++++++False
print(isfloat("%2B1.3P1"))++++++++++++++++False
print(isfloat("-%2B1"))+++++++++++++++++++False
print(isfloat("(1)"))+++++++++++++++++++False+++++++++++brackets+not+interpreted|1370339|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

<h2>Python method to check for float:</h2>
<pre><code>def is_float(element: Any) -&gt; bool:
 try:
 float(element)
 return True
 except ValueError:
 return False
</code></pre>
Always do unit testing. What is, and is not a float may surprise you:
<pre><code>Command to parse Is it a float? Comment
-------------------------------------- --------------- ------------
print(isfloat(&quot;&quot;)) False
print(isfloat(&quot;1234567&quot;)) True 
print(isfloat(&quot;NaN&quot;)) True nan is also float
print(isfloat(&quot;NaNananana BATMAN&quot;)) False
print(isfloat(&quot;123.456&quot;)) True
print(isfloat(&quot;123.E4&quot;)) True
print(isfloat(&quot;.1&quot;)) True
print(isfloat(&quot;1,234&quot;)) False
print(isfloat(&quot;NULL&quot;)) False case insensitive
print(isfloat(&quot;,1&quot;)) False 
print(isfloat(&quot;123.EE4&quot;)) False 
print(isfloat(&quot;6.523537535629999e-07&quot;)) True
print(isfloat(&quot;6e777777&quot;)) True This is same as Inf
print(isfloat(&quot;-iNF&quot;)) True
print(isfloat(&quot;1.797693e+308&quot;)) True
print(isfloat(&quot;infinity&quot;)) True
print(isfloat(&quot;infinity and BEYOND&quot;)) False
print(isfloat(&quot;12.34.56&quot;)) False Two dots not allowed.
print(isfloat(&quot;#56&quot;)) False
print(isfloat(&quot;56%&quot;)) False
print(isfloat(&quot;0E0&quot;)) True
print(isfloat(&quot;x86E0&quot;)) False
print(isfloat(&quot;86-5&quot;)) False
print(isfloat(&quot;True&quot;)) False Boolean is not a float. 
print(isfloat(True)) True Boolean is a float
print(isfloat(&quot;+1e1^5&quot;)) False
print(isfloat(&quot;+1e1&quot;)) True
print(isfloat(&quot;+1e1.3&quot;)) False
print(isfloat(&quot;+1.3P1&quot;)) False
print(isfloat(&quot;-+1&quot;)) False
print(isfloat(&quot;(1)&quot;)) False brackets not interpreted
</code></pre>

blocks|key|1370355|text|'1.43'.replace('.','',1).isdigit()|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1370356|仅当存在或不存在‘’时才返回true。在数字字符串中。|unstyled|offset|length|style|CODE|1370357|'1.4.3'.replace('.','',1).isdigit()|1370358|将返回false|1370359|'1.ww'.replace('.','',1).isdigit()|1370360|1370361|entityMap^0|0|E|4|0|0|3|5|0|0|3|5|0^^$0|@$1|2|3|4|5|6|7|T|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|U|8|@$G|V|H|W|I|J]]|9|@]|A|$]]|$1|K|3|L|5|6|7|X|8|@]|9|@]|A|$B|C]]|$1|M|3|N|5|F|7|Y|8|@$G|Z|H|10|I|J]]|9|@]|A|$]]|$1|O|3|P|5|6|7|11|8|@]|9|@]|A|$B|C]]|$1|Q|3|N|5|F|7|12|8|@$G|13|H|14|I|J]]|9|@]|A|$]]|$1|R|3|-4|5|F|7|15|8|@]|9|@]|A|$]]]|S|$]]

<pre><code>'1.43'.replace('.','',1).isdigit()
</code></pre>

which will return <code>true</code> only if there is one or no '.' in the string of digits.
 

<pre><code>'1.4.3'.replace('.','',1).isdigit()
</code></pre>

will return <code>false</code>
 

<pre><code>'1.ww'.replace('.','',1).isdigit()
</code></pre>

will return <code>false</code>

blocks|key|1370411|text|str(strval).isdigit()|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1370412|看起来很简单。|unstyled|1370413|处理中以字符串、整型或浮点型形式存储的值|1370414|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|L|8|@]|9|@]|A|$]]|$1|G|3|H|5|F|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|F|7|N|8|@]|9|@]|A|$]]]|J|$]]

<pre><code>str(strval).isdigit()
</code></pre>

seems to be simple. 

Handles values stored in as a string or int or float

blocks|key|1585543|text|我使用了前面提到的函数，但很快我注意到字符串"Nan“、"Inf”及其变体被视为数字。所以我建议你改进函数的版本，它将在这些类型的输入上返回false，并且不会失败"1e3“变体：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1585544|def+is_float(text):
++++#+check+for+nan/infinity+etc.
++++if+text.isalpha():
++++++++return+False
++++try:
++++++++float(text)
++++++++return+True
++++except+ValueError:
++++++++return+False|code-block|syntax|javascript|1585545|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I used the function already mentioned, but soon I notice that strings as "Nan", "Inf" and it's variation are considered as number. So I propose you improved version of the function, that will return false on those type of input and will not fail "1e3" variants:

<pre><code>def is_float(text):
 # check for nan/infinity etc.
 if text.isalpha():
 return False
 try:
 float(text)
 return True
 except ValueError:
 return False
</code></pre>

blocks|key|1370545|text|我正在寻找一些类似的代码，但看起来使用try/excepts是最好的方法。这是我正在使用的代码。如果输入无效，它包含一个重试功能。我需要检查输入是否大于0，如果大于0，则将其转换为浮点数。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1370546|def+cleanInput(question,retry=False):+
++++inputValue+=+input("\n\nOnly+positive+numbers+can+be+entered,+please+re-enter+the+value.\n\n{}".format(question))+if+retry+else+input(question)
++++try:
++++++++if+float(inputValue)+<=+0+:+raise+ValueError()
++++++++else+:+return(float(inputValue))
++++except+ValueError+:+return(cleanInput(question,retry=True))


willbefloat+=+cleanInput("Give+me+the+number:+")|code-block|syntax|javascript|1370547|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I was looking for some similar code, but it looks like using try/excepts is the best way.
Here is the code I'm using. It includes a retry function if the input is invalid. I needed to check if the input was greater than 0 and if so convert it to a float.

<pre><code>def cleanInput(question,retry=False): 
 inputValue = input("\n\nOnly positive numbers can be entered, please re-enter the value.\n\n{}".format(question)) if retry else input(question)
 try:
 if float(inputValue) &lt;= 0 : raise ValueError()
 else : return(float(inputValue))
 except ValueError : return(cleanInput(question,retry=True))


willbefloat = cleanInput("Give me the number: ")
</code></pre>

blocks|key|1370588|text|为了方便起见，这里提供了另一种方法。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1370589|>>>+all([i.isnumeric()+for+i+in+'1.2'.split('.',1)])
True
>>>+all([i.isnumeric()+for+i+in+'2'.split('.',1)])
True
>>>+all([i.isnumeric()+for+i+in+'2.f'.split('.',1)])
False|code-block|syntax|javascript|1370590|编辑:我确信它不会支持浮点数的所有情况，特别是当有一个指数的时候。为了解决这个问题，它看起来像这样。这将返回True，只有val是一个浮点数，而int返回False，但它的性能可能不如regex。|1370591|>>>+def+isfloat(val):
...+++++return+all([+[any([i.isnumeric(),+i+in+['.','e']])+for+i+in+val],++len(val.split('.'))+==+2]+)
...
>>>+isfloat('1')
False
>>>+isfloat('1.2')
True
>>>+isfloat('1.2e3')
True
>>>+isfloat('12e3')
False|1370592|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Just for variety here is another method to do it.

<pre><code>&gt;&gt;&gt; all([i.isnumeric() for i in '1.2'.split('.',1)])
True
&gt;&gt;&gt; all([i.isnumeric() for i in '2'.split('.',1)])
True
&gt;&gt;&gt; all([i.isnumeric() for i in '2.f'.split('.',1)])
False
</code></pre>

Edit: Im sure it will not hold up to all cases of float though especially when there is an exponent. To solve that it looks like this. This will return True only val is a float and False for int but is probably less performant than regex. 

<pre><code>&gt;&gt;&gt; def isfloat(val):
... return all([ [any([i.isnumeric(), i in ['.','e']]) for i in val], len(val.split('.')) == 2] )
...
&gt;&gt;&gt; isfloat('1')
False
&gt;&gt;&gt; isfloat('1.2')
True
&gt;&gt;&gt; isfloat('1.2e3')
True
&gt;&gt;&gt; isfloat('12e3')
False
</code></pre>

blocks|key|1585670|text|尝试转换为float。如果出现错误，则打印ValueError异常。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1585671|try:
++++x+=+float('1.23')
++++print('val=',x)
++++y+=+float('abc')
++++print('val=',y)
except+ValueError+as+err:
++++print('floatErr;',err)|code-block|syntax|javascript|1585672|输出：|1585673|val=+1.23
floatErr:+could+not+convert+string+to+float:+'abc'|1585674|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Try to convert to float. If there is an error, print the ValueError exception.

<pre><code>try:
 x = float('1.23')
 print('val=',x)
 y = float('abc')
 print('val=',y)
except ValueError as err:
 print('floatErr;',err)
</code></pre>

Output:

<pre><code>val= 1.23
floatErr: could not convert string to float: 'abc'
</code></pre>

blocks|key|1370643|text|将字典作为参数传递，它将转换字符串，这些字符串可以转换为浮点型，并保留其他字符串|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1370644|def+covertDict_float(data):
++++++++for+i+in+data:
++++++++++++if+data[i].split(".")[0].isdigit():
++++++++++++++++try:
++++++++++++++++++++data[i]+=+float(data[i])
++++++++++++++++except:
++++++++++++++++++++continue
++++++++return+data|code-block|syntax|javascript|1370645|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Passing dictionary as argument it will convert strings which can be converted to float and will leave others 

<pre><code>def covertDict_float(data):
 for i in data:
 if data[i].split(".")[0].isdigit():
 try:
 data[i] = float(data[i])
 except:
 continue
 return data
</code></pre>

blocks|key|1370679|text|您可以使用try-except-else子句，这将捕获当传递的值无法转换为浮点数时引发的任何转换/值错误|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1370680|1370681|++def+try_parse_float(item):
++++++result+=+None
++++++try:
++++++++float(item)
++++++except:
++++++++pass
++++++else:
++++++++result+=+float(item)
++++++return+result|code-block|syntax|javascript|1370682|entityMap^0|5|3|9|6|G|4|0|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@$9|O|A|P|B|C]|$9|Q|A|R|B|C]|$9|S|A|T|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|U|8|@]|D|@]|E|$]]|$1|G|3|H|5|I|7|V|8|@]|D|@]|E|$J|K]]|$1|L|3|-4|5|6|7|W|8|@]|D|@]|E|$]]]|M|$]]

You can use the <code>try</code>-<code>except</code>-<code>else</code> clause , this will catch any conversion/ value errors raised when the value passed cannot be converted to a float
<hr />
<pre><code> def try_parse_float(item):
 result = None
 try:
 float(item)
 except:
 pass
 else:
 result = float(item)
 return result
</code></pre>

blocks|key|1585820|text|似乎很多正则表达式都会遗漏这样或那样的东西。到目前为止，这对我来说是有效的：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1585821|(?i)%5E\s*[%2B-]?(?:inf(inity)?%7Cnan%7C(?:\d%2B\.?\d*%7C\.\d%2B)(?:e[%2B-]?\d%2B)?)\s*$|code-block|syntax|javascript|1585822|它允许无穷大(或inf)带符号、nan、小数点前无数字和前导/尾随空格(如果需要)。需要%5E和$来避免部分匹配像1.2f-2这样的东西作为1.2。|offset|length|style|CODE|1585823|如果您需要解析某些文件，其中D用于双精度科学记数法，则可以使用[ed]而不仅仅是e。您可能希望在以后替换它，或者在检查之前替换它们，因为float()函数不允许这样做。|1585824|entityMap^0|0|0|18|1|1A|1|1J|6|1W|3|0|E|1|V|4|14|1|1W|7|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@$I|T|J|U|K|L]|$I|V|J|W|K|L]|$I|X|J|Y|K|L]|$I|Z|J|10|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|11|8|@$I|12|J|13|K|L]|$I|14|J|15|K|L]|$I|16|J|17|K|L]|$I|18|J|19|K|L]]|9|@]|A|$]]|$1|O|3|-4|5|6|7|1A|8|@]|9|@]|A|$]]]|P|$]]

It seems many regex given miss one thing or another. This has been working for me so far:
<pre><code>(?i)^\s*[+-]?(?:inf(inity)?|nan|(?:\d+\.?\d*|\.\d+)(?:e[+-]?\d+)?)\s*$
</code></pre>
It allows for infinity (or inf) with sign, nan, no digit before the
decimal, and leading/trailing spaces (if desired). The <code>^</code> and <code>$</code> are
needed to keep from partially matching something like <code>1.2f-2</code> as <code>1.2</code>.
You could use <code>[ed]</code> instead of just <code>e</code> if you need to parse some files
where <code>D</code> is used for double-precision scientific notation. You would
want to replace it afterward or just replace them before checking since
the <code>float()</code> function won't allow it.

blocks|key|1370763|text|我找到了一种同样可行的方法。需要验证这一点。第一次把东西放在这里。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1370764|def+isfloat(a_str):
++++try:
++++++++x=float(a_str)
++++++++if+x%251+==+0:
++++++++++++return+False
++++++++elif+x%251+!=+0:+#an+else+also+do
++++++++++++return+True
++++except+Exception+as+error:
++++++++++++return+False|code-block|syntax|javascript|1370765|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I found a way that could also work. need to verify this. first time putting something here.
<pre><code>def isfloat(a_str):
 try:
 x=float(a_str)
 if x%1 == 0:
 return False
 elif x%1 != 0: #an else also do
 return True
 except Exception as error:
 return False
</code></pre>

blocks|key|1370801|text|这就像一个护身符：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1370802|[dict([a,int(x)+if+isinstance(x,+str)
+and+x.isnumeric()+else+float(x)+if+isinstance(x,+str)
+and+x.replace('.',+'',+1).isdigit()+else+x]+for+a,+x+in+json_data.items())][0]|code-block|syntax|javascript|1370803|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

This works like a charm:
<pre><code>[dict([a,int(x) if isinstance(x, str)
 and x.isnumeric() else float(x) if isinstance(x, str)
 and x.replace('.', '', 1).isdigit() else x] for a, x in json_data.items())][0]
</code></pre>

blocks|key|1370902|text|我已经编写了我自己的函数。我使用floatN()或floatZ()而不是float(值)。如果值不能转换为浮点数，则返回None或0.0。我将它们保存在一个名为safeCasts的模块中。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1370903|def+floatN(value):
++++try:
++++++++if+value+is+not+None:
++++++++++++fvalue+=+float(value)
++++++++else:
++++++++++++fvalue+=+None
++++except+ValueError:
++++++++fvalue+=+None

++++return+fvalue


def+floatZ(value):
++++try:
++++++++if+value+is+not+None:
++++++++++++fvalue+=+float(value)
++++++++else:
++++++++++++fvalue+=+0.0
++++except+ValueError:
++++++++fvalue+=+0.0

++++return+fvalue|code-block|syntax|javascript|1370904|在其他模块中，我导入它们|1370905|from+safeCasts+import+floatN,+floatZ|1370906|然后使用floatN(值)或floatZ(值)代替float()。显然，您可以将此技术用于所需的任何强制转换函数。|1370907|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

I've written my own functions. Instead of float(value), I use floatN() or floatZ(). which return None or 0.0 if the value can't be cast as a float. I keep them in a module I've called safeCasts.
<pre><code>def floatN(value):
 try:
 if value is not None:
 fvalue = float(value)
 else:
 fvalue = None
 except ValueError:
 fvalue = None

 return fvalue


def floatZ(value):
 try:
 if value is not None:
 fvalue = float(value)
 else:
 fvalue = 0.0
 except ValueError:
 fvalue = 0.0

 return fvalue
</code></pre>
In other modules I import them
<pre><code>from safeCasts import floatN, floatZ
</code></pre>
then use floatN(value) or floatZ(value) instead of float(). Obviously, you can use this technique for any cast function you need.

I've got some Python code that runs through a list of strings and converts them to integers or floating point numbers if possible. Doing this for integers is pretty easy

<pre><code>if element.isdigit():
 newelement = int(element)
</code></pre>

Floating point numbers are more difficult. Right now I'm using <code>partition('.')</code> to split the string and checking to make sure that one or both sides are digits.

<pre><code>partition = element.partition('.')
if (partition[0].isdigit() and partition[1] == '.' and partition[2].isdigit()) 
 or (partition[0] == '' and partition[1] == '.' and partition[2].isdigit()) 
 or (partition[0].isdigit() and partition[1] == '.' and partition[2] == ''):
 newelement = float(element)
</code></pre>

This works, but obviously the if statement for that is a bit of a bear. The other solution I considered is to just wrap the conversion in a try/catch block and see if it succeeds, as described in <a href="https://stackoverflow.com/questions/354038/checking-if-string-is-a-number-python">this question</a>.

Anyone have any other ideas? Opinions on the relative merits of the partition and try/catch approaches?

Checking if a string can be converted to float in Python

单元测试

Python

我有一些Python代码，它遍历字符串列表，并在可能的情况下将它们转换为整数或浮点数。对整数执行此操作非常简单if element.isdigit():  newelement = int(element)浮点数的难度更大。现在，我使用partition('.')来拆分字符串，并检查以确保其中一端或两端都是数字。par...

问检查字符串是否可以在Python中转换为浮点型
EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问检查字符串是否可以在Python中转换为浮点型EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问检查字符串是否可以在Python中转换为浮点型
EN