blocks|key|185051|text|您可以使用round函数，该函数的第一个参数是数字，第二个参数是小数点后的精度。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|185052|在您的情况下，它将是：|185053|answer+=+str(round(answer,+2))|code-block|syntax|javascript|185054|entityMap|0|LINK|mutability|MUTABLE|url|http://docs.python.org/library/functions.html#round^0|5|5|5|5|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]]|D|@$9|X|A|Y|1|Z]]|E|$]]|$1|F|3|G|5|6|7|10|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|11|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|12|8|@]|D|@]|E|$]]]|N|$O|$5|P|Q|R|E|$S|T]]]]

You can use the <a href="http://docs.python.org/library/functions.html#round" rel="noreferrer"><code>round</code></a> function, which takes as its first argument the number and the second argument is the precision after the decimal point.

In your case, it would be:

<pre><code>answer = str(round(answer, 2))
</code></pre>

blocks|key|4691020|text|如果你只想打印出四舍五入的结果，你可以使用从Python3.6开始引入的f-strings。语法与str.format()的format+string+syntax相同，不同之处在于您将f放在文字字符串的前面，并将变量直接放在字符串中的花括号内。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|4691021|.2f表示四舍五入到两位小数：|4691022|number+=+3.1415926
print(f"The+number+rounded+to+two+decimal+places+is+{number:.2f}")|code-block|syntax|javascript|4691023|输出：|4691024|The+number+rounded+to+two+decimal+places+is+3.14|4691025|entityMap|0|LINK|mutability|MUTABLE|url|https://www.python.org/dev/peps/pep-0498/|1|https://docs.python.org/3/library/stdtypes.html#str.format|2|https://docs.python.org/3/library/string.html#format-string-syntax^0|1D|C|2L|1|10|9|0|1D|C|1|1Q|K|2|0|0|3|0|0|0|0^^$0|@$1|2|3|4|5|6|7|12|8|@$9|13|A|14|B|C]|$9|15|A|16|B|C]]|D|@$9|17|A|18|1|19]|$9|1A|A|1B|1|1C]|$9|1D|A|1E|1|1F]]|E|$]]|$1|F|3|G|5|6|7|1G|8|@$9|1H|A|1I|B|C]]|D|@]|E|$]]|$1|H|3|I|5|J|7|1J|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|1K|8|@]|D|@]|E|$]]|$1|O|3|P|5|J|7|1L|8|@]|D|@]|E|$K|L]]|$1|Q|3|-4|5|6|7|1M|8|@]|D|@]|E|$]]]|R|$S|$5|T|U|V|E|$W|X]]|Y|$5|T|U|V|E|$W|Z]]|10|$5|T|U|V|E|$W|11]]]]

If you just want to print the rounded result out, you can use the <a href="https://www.python.org/dev/peps/pep-0498/" rel="noreferrer">f-strings</a> introduced since Python 3.6. The syntax is the same as <a href="https://docs.python.org/3/library/stdtypes.html#str.format" rel="noreferrer"><code>str.format()</code></a>'s <a href="https://docs.python.org/3/library/string.html#format-string-syntax" rel="noreferrer">format string syntax</a>, except you put a <code>f</code> in front of the literal string, and you put the variables directly in the string, within the curly braces.
<code>.2f</code> indicates rounding to two decimal places:
<pre><code>number = 3.1415926
print(f&quot;The number rounded to two decimal places is {number:.2f}&quot;)
</code></pre>
Output:
<pre><code>The number rounded to two decimal places is 3.14
</code></pre>

blocks|key|185065|text|您可以使用round函数。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|185066|round(80.23456,+3)|code-block|syntax|javascript|185067|会给你一个80.234的答案|185068|在您的示例中，使用|185069|answer+=+str(round(answer,+2))|185070|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|$]]

You can use the round function.
<pre><code>round(80.23456, 3)
</code></pre>
will give you an answer of 80.234
In your case, use
<pre><code>answer = str(round(answer, 2))
</code></pre>

blocks|key|4690896|text|float(str(round(answer,+2)))
float(str(round(0.0556781255,+2)))|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|4690897|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>float(str(round(answer, 2)))
float(str(round(0.0556781255, 2)))
</code></pre>

blocks|key|4690840|text|只需使用带有%25.2f的格式，就可以将小数舍入到2位小数。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4690841|def+printC(answer):
++++print+"\nYour+Celsius+value+is+%25.2f+C.\n"+%25+answer|code-block|syntax|javascript|4690842|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|$]]

Just use the formatting with %.2f which gives you rounding down to 2 decimals.

<pre><code>def printC(answer):
 print "\nYour Celsius value is %.2f C.\n" % answer
</code></pre>

blocks|key|185171|text|如果您不仅需要舍入结果，还需要对舍入结果进行数学运算，那么您可以使用decimal.Decimal+https://docs.python.org/2/library/decimal.html|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|185172|from+decimal+import+Decimal,+ROUND_DOWN

Decimal('7.325').quantize(Decimal('.01'),+rounding=ROUND_DOWN)
Decimal('7.32')+|code-block|syntax|javascript|185173|entityMap|0|LINK|mutability|MUTABLE|url|https://docs.python.org/2/library/decimal.html^0|Y|F|1E|1A|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@$9|V|A|W|1|X]]|E|$]]|$1|F|3|G|5|H|7|Y|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]]|L|$M|$5|N|O|P|E|$Q|R]]]]

If you need not only round result but elso do math operations with round result, then you can use <code>decimal.Decimal</code> <a href="https://docs.python.org/2/library/decimal.html" rel="noreferrer">https://docs.python.org/2/library/decimal.html</a>
<pre><code>from decimal import Decimal, ROUND_DOWN

Decimal('7.325').quantize(Decimal('.01'), rounding=ROUND_DOWN)
Decimal('7.32') 
</code></pre>

blocks|key|4690805|text|您可以使用python+"%25“的字符串格式化运算符。"%25.2f“表示小数点后的2位数字。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4690806|def+typeHere():
++++try:
++++++++Fahrenheit+=+int(raw_input("Hi!+Enter+Fahrenheit+value,+and+get+it+in+Celsius!\n"))
++++except+ValueError:
++++++++print+"\nYour+insertion+was+not+a+digit!"
++++++++print+"We've+put+your+Fahrenheit+value+to+50!"
++++++++Fahrenheit+=+50
++++return+Fahrenheit

def+formeln(Fahrenheit):
++++Celsius+=+(Fahrenheit+-+32.0)+*+5.0/9.0
++++return+Celsius

def+printC(answer):
++++print+"\nYour+Celsius+value+is+%25.2f+C.\n"+%25+answer

def+main():
++++printC(formeln(typeHere()))

main()|code-block|syntax|javascript|4690807|http://docs.python.org/2/library/stdtypes.html#string-formatting|offset|length|4690808|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|0|1S|0|0^^$0|@$1|2|3|4|5|6|7|R|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|S|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|T|8|@]|9|@$I|U|J|V|1|W]]|A|$]]|$1|K|3|-4|5|6|7|X|8|@]|9|@]|A|$]]]|L|$M|$5|N|O|P|A|$Q|H]]]]

You can use the string formatting operator of python "%".
"%.2f" means 2 digits after the decimal point.

<pre><code>def typeHere():
 try:
 Fahrenheit = int(raw_input("Hi! Enter Fahrenheit value, and get it in Celsius!\n"))
 except ValueError:
 print "\nYour insertion was not a digit!"
 print "We've put your Fahrenheit value to 50!"
 Fahrenheit = 50
 return Fahrenheit

def formeln(Fahrenheit):
 Celsius = (Fahrenheit - 32.0) * 5.0/9.0
 return Celsius

def printC(answer):
 print "\nYour Celsius value is %.2f C.\n" % answer

def main():
 printC(formeln(typeHere()))

main()
</code></pre>

<a href="http://docs.python.org/2/library/stdtypes.html#string-formatting" rel="nofollow">http://docs.python.org/2/library/stdtypes.html#string-formatting</a>

blocks|key|4690901|text|下面是我使用的一个例子：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4690902|def+volume(self):
++++return+round(pi+*+self.radius+**+2+*+self.height,+2)

def+surface_area(self):
++++return+round((2+*+pi+*+self.radius+*+self.height)+%2B+(2+*+pi+*+self.radius+**+2),+2)|code-block|syntax|javascript|4690903|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|$]]

Here is an example that I used:

<pre><code>def volume(self):
 return round(pi * self.radius ** 2 * self.height, 2)

def surface_area(self):
 return round((2 * pi * self.radius * self.height) + (2 * pi * self.radius ** 2), 2)
</code></pre>

blocks|key|185137|text|round(12.3956+-+0.005,+2)++#+minus+0.005,+then+round.|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|185138|答案来自：https://stackoverflow.com/a/29651462/8025086|unstyled|offset|length|185139|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/29651462/8025086^0|0|5|18|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|R|8|@]|9|@$G|S|H|T|1|U]]|A|$]]|$1|I|3|-4|5|F|7|V|8|@]|9|@]|A|$]]]|J|$K|$5|L|M|N|A|$O|P]]]]

<pre><code>round(12.3956 - 0.005, 2) # minus 0.005, then round.
</code></pre>

The answer is from: <a href="https://stackoverflow.com/a/29651462/8025086">https://stackoverflow.com/a/29651462/8025086</a>

blocks|key|185238|text|为了避免来自round()的令人惊讶的值，这是我的方法：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|185239|Round+=+lambda+x,+n:+eval('"%25.'%2Bstr(int(n))%2B'f"+%25+'%2Brepr(int(x)%2Bround(float('.'%2Bstr(float(x)).split('.')[1]),n)))

print(Round(2,+2))+++++++#+2.00
print(Round(2.675,+2))+++#+2.68|code-block|syntax|javascript|185240|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|$]]

To avoid surprising value from round() this is my approche:
<pre><code>Round = lambda x, n: eval('&quot;%.'+str(int(n))+'f&quot; % '+repr(int(x)+round(float('.'+str(float(x)).split('.')[1]),n)))

print(Round(2, 2)) # 2.00
print(Round(2.675, 2)) # 2.68
</code></pre>

blocks|key|185257|text|from+decimal+import+Decimal,+ROUND_HALF_UP

#+Here+are+all+your+options+for+rounding:
#+This+one+offers+the+most+out+of+the+box+control
#+ROUND_05UP+++++++ROUND_DOWN+++++++ROUND_HALF_DOWN++ROUND_HALF_UP
#+ROUND_CEILING++++ROUND_FLOOR++++++ROUND_HALF_EVEN++ROUND_UP

our_value+=+Decimal(16.0/7)
output+=+Decimal(our_value.quantize(Decimal('.01'),+
rounding=ROUND_HALF_UP))
print+output|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|185258|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>from decimal import Decimal, ROUND_HALF_UP

# Here are all your options for rounding:
# This one offers the most out of the box control
# ROUND_05UP ROUND_DOWN ROUND_HALF_DOWN ROUND_HALF_UP
# ROUND_CEILING ROUND_FLOOR ROUND_HALF_EVEN ROUND_UP

our_value = Decimal(16.0/7)
output = Decimal(our_value.quantize(Decimal('.01'), 
rounding=ROUND_HALF_UP))
print output
</code></pre>

blocks|key|4690922|text|不知道为什么，但是'{:0.2f}'.format(0.5357706)给了我'0.54‘。对我来说唯一有效的解决方案(python+3.6)是：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4690923|def+ceil_floor(x):
++++import+math
++++return+math.ceil(x)+if+x+<+0+else+math.floor(x)

def+round_n_digits(x,+n):
++++import+math
++++return+ceil_floor(x+*+math.pow(10,+n))+/+math.pow(10,+n)

round_n_digits(-0.5357706,+2)+->+-0.53+
round_n_digits(0.5357706,+2)+->+0.53|code-block|syntax|javascript|4690924|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|$]]

Not sure why, but '{:0.2f}'.format(0.5357706) gives me '0.54'.
The only solution that works for me (python 3.6) is the following:

<pre><code>def ceil_floor(x):
 import math
 return math.ceil(x) if x &lt; 0 else math.floor(x)

def round_n_digits(x, n):
 import math
 return ceil_floor(x * math.pow(10, n)) / math.pow(10, n)

round_n_digits(-0.5357706, 2) -&gt; -0.53 
round_n_digits(0.5357706, 2) -&gt; 0.53
</code></pre>

I am getting a lot of decimals in the output of this code (Fahrenheit to Celsius converter).

My code currently looks like this:

<pre><code>def main():
 printC(formeln(typeHere()))

def typeHere():
 global Fahrenheit
 try:
 Fahrenheit = int(raw_input("Hi! Enter Fahrenheit value, and get it in Celsius!\n"))
 except ValueError:
 print "\nYour insertion was not a digit!"
 print "We've put your Fahrenheit value to 50!"
 Fahrenheit = 50
 return Fahrenheit

def formeln(c):
 Celsius = (Fahrenheit - 32.00) * 5.00/9.00
 return Celsius

def printC(answer):
 answer = str(answer)
 print "\nYour Celsius value is " + answer + " C.\n"



main()
</code></pre>

So my question is, how do I make the program round every answer to the 2nd decimal place?

How to round to 2 decimals with Python?

我在这个代码的输出中得到了很多小数(华氏到摄氏度的转换器)。我的代码目前看起来像这样：def main():    printC(formeln(typeHere()))def typeHere():    global Fahrenheit    try:        Fahrenheit = int(raw_input("Hi! Enter Fahrenheit value, and get

问如何用Python四舍五入到2位小数？
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回答 12

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问如何用Python四舍五入到2位小数？EN

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问如何用Python四舍五入到2位小数？
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