Why you should care

• Immediately inside parentheses, brackets or braces.

  Yes: spam(ham[1], {eggs: 2})
  No:  spam( ham[ 1 ], { eggs: 2 } )
  

• Immediately before a:

  • comma

  • semicolon

  • colon (except when using as slice operator)

    Yes: if x == 4: print x, y; x, y = y, x
    No:  if x == 4 : print x , y ; x , y = y , x

• Immediately before the open parenthesis that starts the argument list of a function call:

  Yes: spam(1)
  No:  spam (1)
  

• Immediately before the open parenthesis that starts an indexing or slicing:

  Yes: dct['key'] = lst[index]
  No:  dct ['key'] = lst [index]
  

• More than one space around an assignment (or other) operator to align it with another.

  Yes:

  x = 1
  y = 2
  long_variable = 3
  

  No:

  x             = 1
  y             = 2
  long_variable = 3

• Don’t use spaces around the = sign when used to indicate a keyword argument or a default parameter value.

  Yes:

  def complex(real, imag=0.0):
      return magic(r=real, i=imag)
  

  No:

  def complex(real, imag = 0.0):
      return magic(r = real, i = imag)

Business Impacts

It is recommended to avoid these in order to ensure the code is more readable and cost effective.

CAST Recommendations

CAST recommends having no space between function name and parenthesis.  The JavaScript style guidelines by Douglas Crockford establish very consistent rules that help the code work well and perform with cost efficiency.

References

https://stackoverflow.com/questions/9765942/space-after-function-name-is-wrong