Round up to Second Decimal Place in Python

Question

How can I round up a number to the second decimal place in python   For example   0 022499999999999999   Should round up to 0 03  0 1111111111111000   Should round up to 0 12  If there is any value in the third decimal place  I want it to always round up leaving me 2 values behind the decimal point

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Extrapolating from Edwin s answer   from math import ceil  floor def float round num  places   0  direction   floor       return direction num    10  places     float 10  places    To use    gt  gt  gt  float round 0 21111  3  ceil    round up  gt  gt  gt  0 212  gt  gt  gt  float round 0 21111  3          round down  gt  gt  gt  0 211  gt  gt  gt  float round 0 21111  3  round   round naturally  gt  gt  gt  0 211

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Python includes the round   function which lets you specify the number of digits you want  From the documentation   round x   n   Return the floating point value x rounded to n digits after the decimal point  If n is omitted  it defaults to zero  The result is a floating point number  Values are rounded to the closest multiple of 10 to the power minus n  if two multiples are equally close  rounding is done away from 0  so  for example  round 0 5  is 1 0 and round -0 5  is -1 0    So you would want to use round x  2  to do normal rounding  To ensure that the number is always rounded up you would need to use the ceil x  function  Similarly  to round down use floor x

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Note that the ceil num   100    100 trick will crash on some degenerate inputs  like 1e308   This may not come up often but I can tell you it just cost me a couple of days   To avoid this   it would be nice if  ceil   and floor   took a decimal places argument  like round   does     Meanwhile  anyone know a clean alternative that won t crash on inputs like this   I had some hopes for the decimal package but it seems to die too    gt  gt  gt  from math import ceil  gt  gt  gt  from decimal import Decimal  ROUND DOWN  ROUND UP  gt  gt  gt  num   0 1111111111000  gt  gt  gt  ceil num   100    100 0 12  gt  gt  gt  float Decimal num  quantize Decimal   01    rounding ROUND UP   0 12  gt  gt  gt  num   1e308  gt  gt  gt  ceil num   100    100 Traceback  most recent call last     File   lt string gt    line 301  in runcode   File   lt interactive input gt    line 1  in  lt module gt  OverflowError  cannot convert float infinity to integer  gt  gt  gt  float Decimal num  quantize Decimal   01    rounding ROUND UP   Traceback  most recent call last     File   lt string gt    line 301  in runcode   File   lt interactive input gt    line 1  in  lt module gt  decimal InvalidOperation    lt class  decimal InvalidOperation  gt     Of course one might say that crashing is the only sane behavior on such inputs  but I would argue that it s not the rounding but the multiplication that s causing the problem  that s why  eg  1e306 doesn t crash   and a cleaner implementation of the round-up-nth-place fn would avoid the multiplication hack

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x   math ceil x   100 0    100 0

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Updated answer  The problem with my original answer  as pointed out in the comments by  jpm  is the behavior at the boundaries  Python 3 makes this even more difficult since it uses  bankers  rounding instead of  old school  rounding  However  in looking into this issue I discovered an even better solution using the decimal library   import decimal  def round up x  place 0       context   decimal getcontext         get the original setting so we can put it back when we re done     original rounding   context rounding       change context to act like ceil       context rounding   decimal ROUND CEILING      rounded   round decimal Decimal str x    place      context rounding   original rounding     return float rounded    Or if you really just want a one-liner   import decimal decimal getcontext   rounding   decimal ROUND CEILING    here s the one-liner float round decimal Decimal str 0 1111    ndigits 2    gt  gt  0 12    Note  this only affects the rounding of  Decimal  round 0 1111  ndigits 2   gt  gt  0 11   Here are some examples   round up 0 022499999999999999  2   gt  gt  0 03 round up 0 1111111111111000  2   gt  gt  0 12 round up 0 1111111111111000  3   gt  gt  0 112  round up 3 4   gt  gt  4 0     jpm - boundaries do what we want round up 0 1  2   gt  gt  0 1 round up 1 1  2   gt  gt  1 1    Note  this still rounds toward  inf   not  away from zero  round up 2 049  2   gt  gt  2 05 round up -2 0449  2   gt  gt  -2 04   We can use it to round to the left of the decimal as well   round up 11  -1   gt  gt  20   We don t multiply by 10  thereby avoiding the overflow mentioned in this answer   round up 1 01e308  -307   gt  gt  1 1e 308   Original Answer  Not recommended   This depends on the behavior you want when considering positive and negative numbers  but if you want something that always rounds to a larger value  e g  2 0449 -  2 05  -2 0449 -  -2 04  then you can do   round x   0 005  2    or a little fancier   def round up x  place       return round x   5   10   -1    place   1    place    This also seems to work as follows   round 144  -1    140 round up 144  -1    150 round up 1e308  -307    1 1e308

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def round up number  ndigits None         start by just rounding the number  as sometimes this rounds it up     result   round number  ndigits if ndigits else 0      if result  lt  number            whoops  the number was rounded down instead  so correct for that         if ndigits                use the type of number provided  e g  float  decimal  fraction             Numerical   type number                add the digit 1 in the correct decimal place             result    Numerical 10     -ndigits               may need to be tweaked slightly if the addition was inexact             result   round result  ndigits          else              result    1   same as 10    -0 for precision of zero digits     return result  assert round up 0 022499999999999999  2     0 03 assert round up 0 1111111111111000  2     0 12  assert round up 1 11  2     1 11 assert round up 1e308  2     1e308

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Here s a simple way to do it that I don t see in the other answers    To round up to the second decimal place    gt  gt  gt  n   0 022499999999999999  gt  gt  gt    gt  gt  gt  - -n   01     01 0 03  gt  gt  gt     Other value    gt  gt  gt  n   0 1111111111111000  gt  gt  gt    gt  gt  gt  - -n   01     01 0 12  gt  gt  gt     With floats there s the occasional value with some minute imprecision  which can be corrected for if you re displaying the values for instance    gt  gt  gt  n   10 1111111111111000  gt  gt  gt    gt  gt  gt  - -n  0 01    0 01 10 120000000000001  gt  gt  gt    gt  gt  gt  f  - -n  0 01    0 01  2f    10 12   gt  gt  gt     A simple roundup function with a parameter to specify precision    gt  gt  gt  roundup   lambda n  p  - -n  10  -p    10  -p  gt  gt  gt    gt  gt  gt    Or if you want to ensure truncation using the f-string method   gt  gt  gt  roundup   lambda n  p  float f  - -n  10  -p    10  -p   p f     gt  gt  gt    gt  gt  gt  roundup 0 111111111  2  0 12  gt  gt  gt  roundup 0 111111111  3  0 112

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Here is a more general one-liner that works for any digits  import math def ceil number  digits  - gt  float  return math ceil  10 0    digits    number     10 0    digits   Example usage   gt  gt  gt  ceil 1 111111  2  1 12  Caveat  as stated by nimeshkiranverma   gt  gt  gt  ceil 1 11  2   1 12   Because  1 11   100 0 has value 111 00000000000001

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from math import ceil  num   0 1111111111000 num   ceil num   100    100 0   See  math ceil documentation round documentation - You ll probably want to check this out anyway for future reference

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The round funtion stated does not works for definate integers like       a 8   round a 3    8 0   a 8 00   round a 3    8 0   a 8 000000000000000000000000   round a 3    8 0   but   works for       r 400 3 0   r       133 33333333333334   round r 3        133 333   Morever the decimals like 2 675 are rounded as 2 67 not 2 68  Better use the other method provided above

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The python round function could be rounding the way not you expected   You can be more specific about the rounding method by using Decimal quantize  eg   from decimal import Decimal  ROUND HALF UP res   Decimal  0 25   quantize Decimal  0 0    rounding ROUND HALF UP  print res     prints 0 3   More reference   https   gist github com jackiekazil 6201722

[python] Round up to Second Decimal Place in Python

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