Round to 5 or other number in Python

Question

Is there a built-in function that can round like the following   10 - gt  10 12 - gt  10 13 - gt  15 14 - gt  15 16 - gt  15 18 - gt  20

User · Accepted Answer

I don t know of a standard function in Python  but this works for me   Python 2  def myround x  base 5       return int base   round float x  base     Python3  def myround x  base 5       return base   round x base    It is easy to see why the above works   You want to make sure that your number divided by 5 is an integer  correctly rounded   So  we first do exactly that  round float x  5  where float is only needed in Python2   and then since we divided by 5  we multiply by 5 as well   The final conversion to int is because round   returns a floating-point value in Python 2   I made the function more generic by giving it a base parameter  defaulting to 5

User · Answer

Here is my C code  If I understand it correctly  it should supposed to be something like this    include  lt stdio h gt   int main    int number   printf  Enter number   n    scanf   d     amp number    if number 5    0      printf  It is multiple of 5 n    else      while number 5    0          number      printf   d n  number           and this also rounds to nearest multiple of 5 instead of just rounding up    include  lt stdio h gt   int main    int number   printf  Enter number   n    scanf   d     amp number    if number 5    0      printf  It is multiple of 5 n    else      while number 5    0          if  number 5  lt  3              number--          else         number      printf  nearest multiple of 5 is   d n  number

User · Answer

No one actually wrote this yet I guess but you can do  round 12  -1  -- gt  10 round 18  -1  -- gt  20

User · Answer

For integers and with Python 3   def divround down value  step       return value  step step   def divround up value  step       return  value step-1   step step   Producing    gt  gt  gt   divround down x 5  for x in range 20    0  0  0  0  0  5  5  5  5  5  10  10  10  10  10  15  15  15  15  15   gt  gt  gt   divround up x 5  for x in range 20    0  5  5  5  5  5  10  10  10  10  10  15  15  15  15  15  20  20  20  20

User · Answer

def round up to base x  base 10       return x    base - x    base  def round down to base x  base 10       return x -  x   base   which gives for base 5   gt  gt  gt   i for i in range 20    0  1   2   3   4   5   6   7   8   9   10  11  12  13  14  15  16  17  18  19    gt  gt  gt   round down to base x i  base 5  for i in range 20    0  0   0   0   0   5   5   5   5   5   10  10  10  10  10  15  15  15  15  15    gt  gt  gt   round up to base x i  base 5  for i in range 20    0  5   5   5   5   5   10  10  10  10  10  15  15  15  15  15  20  20  20  20   for base 10   gt  gt  gt   i for i in range 20    0  1   2   3   4   5   6   7   8   9   10  11  12  13  14  15  16  17  18  19    gt  gt  gt   round down to base x i  base 10  for i in range 20    0  0   0   0   0   0   0   0   0   0   10  10  10  10  10  10  10  10  10  10    gt  gt  gt   round up to base x i  base 10  for i in range 20    0  10  10  10  10  10  10  10  10  10  10  20  20  20  20  20  20  20  20  20   tested in Python 3 7 9

User · Answer

It s just a matter of scaling       gt  gt  gt  a  10 11 12 13 14 15 16 17 18 19 20   gt  gt  gt  for b in a          int round b 5 0  5 0       10 10 10 15 15 15 15 15 20 20 20

User · Answer

In case someone needs  financial rounding   0 5 rounds always up    def myround x  base 5       roundcontext   decimal Context rounding decimal ROUND HALF UP      decimal setcontext roundcontext      return int base  float decimal Decimal x base  quantize decimal Decimal  0        As per documentation other rounding options are      ROUND CEILING  towards Infinity     ROUND DOWN  towards zero     ROUND FLOOR  towards -Infinity     ROUND HALF DOWN  to nearest with ties going towards zero     ROUND HALF EVEN  to nearest with ties going to nearest even integer     ROUND HALF UP  to nearest with ties going away from zero   or   ROUND UP  away from zero     ROUND 05UP  away from zero if last digit after rounding towards zero would have been 0 or 5  otherwise towards zero    By default Python uses ROUND HALF EVEN as it has some statistical advantages  the rounded results are not biased

User · Answer

def round to next5 n       return n    5 - n    5

User · Answer

What about this    def divround value  step        return divmod value  step  0    step

User · Answer

You can    trick    int   into rounding off instead of rounding down by adding 0 5 to the  number you pass to int

User · Answer

round x   n    values are rounded to the closest multiple of 10 to the power minus n  So if n is negative     def round5 x       return int round x 2  -1     2   Since 10   5   2  you can use integer division and multiplication with 2  rather than float division and multiplication with 5 0  Not that that matters much  unless you like bit shifting  def round5 x       return int round x  lt  lt  1  -1    gt  gt  1

User · Answer

For rounding to non-integer values  such as 0 05   def myround x  prec 2  base  05     return round base   round float x  base  prec    I found this useful since I could just do a search and replace in my code to change  round   to  myround    without having to change the parameter values

User · Answer

Sorry  I wanted to comment on Alok Singhai s answer  but it won t let me due to a lack of reputation     Anyway  we can generalize one more step and go   def myround x  base 5       return base   round float x    base    This allows us to use non-integer bases  like  25 or any other fractional base

User · Answer

Removing the  rest  would work   rounded   int val  - int val    5   If the value is aready an integer   rounded   val - val   5   As a function   def roundint value  base 5       return int value  - int value    int base

User · Answer

Modified version of divround  -   def divround value  step  barrage       result  rest   divmod value  step      return result step if rest  lt  barrage else  result 1  step

User · Answer

Another way to do this  without explicit multiplication or division operators    def rnd x  b 5       return round x   min - x   b   b -  x   b   key abs

User · Answer

Next multiple of 5  Consider 51 needs to be converted to 55   code here  mark   51  r   100 - mark  a   r 5  new mark   mark   a

User · Answer

Use    gt  gt  gt  def round to nearest n  m           r   n   m         return n   m - r if r   r  gt   m else n - r   It does not use multiplication and will not convert from to floats   Rounding to the nearest multiple of 10    gt  gt  gt  for n in range -21  30  3   print    3d     gt     3d   format n  round to nearest n  10    -21    gt   -20 -18    gt   -20 -15    gt   -10 -12    gt   -10  -9    gt   -10  -6    gt   -10  -3    gt     0   0    gt     0   3    gt     0   6    gt    10   9    gt    10  12    gt    10  15    gt    20  18    gt    20  21    gt    20  24    gt    20  27    gt    30   As you can see  it works for both negative and positive numbers  Ties  e g  -15 and 15  will always be rounded upwards   A similar example that rounds to the nearest multiple of 5  demonstrating that it also behaves as expected for a different  base     gt  gt  gt  for n in range -21  30  3   print    3d     gt     3d   format n  round to nearest n  5    -21    gt   -20 -18    gt   -20 -15    gt   -15 -12    gt   -10  -9    gt   -10  -6    gt    -5  -3    gt    -5   0    gt     0   3    gt     5   6    gt     5   9    gt    10  12    gt    10  15    gt    15  18    gt    20  21    gt    20  24    gt    25  27    gt    25

[python] Round to 5 (or other number) in Python

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