How to write inline if statement for print

Question

I need to print some stuff only when a boolean variable is set to True  So  after looking at this  I tried with a simple example    gt  gt  gt  a   100  gt  gt  gt  b   True  gt  gt  gt  print a if b   File   lt stdin gt    line 1     print a if b                SyntaxError  invalid syntax     Same thing if I write print a if b  True   What am I missing here

User · Answer

If you don t want to from   future   import print function you can do the following   a   100 b   True print a if b else        Note the comma  print  see no new line    Which prints   100 see no new line   If you re not aversed to from   future   import print function or are using python 3 or later   from   future   import print function a   False b   100 print b if a else     end         Adding the else is the only change you need to make to make your code syntactically correct  you need the else for the conditional expression  the  in line if else blocks     The reason I didn t use None or 0 like others in the thread have used  is because using None 0 would cause the program to print None or print 0 in the cases where b is False   If you want to read about this topic I ve included a link to the release notes for the patch that this feature was added to Python   The  pattern  above is very similar to the pattern shown in PEP 308      This syntax may seem strange and backwards  why does the condition go   in the middle of the expression  and not in the front as in C s c   x     y  The decision was checked by applying the new syntax to the   modules in the standard library and seeing how the resulting code   read  In many cases where a conditional expression is used  one value   seems to be the  common case  and one value is an  exceptional case     used only on rarer occasions when the condition isn t met  The   conditional syntax makes this pattern a bit more obvious       contents     doc     n   if doc else       So I think overall this is a reasonable way of approching it but you can t argue with the simplicity of   if logging  print data

User · Answer

Well why don t you simply write   if b      print a else      print  b is false

User · Answer

Inline if-else EXPRESSION must always contain else clause  e g   a   1 if b else 0   If you want to leave your  a  variable value unchanged - assing old  a  value  else is still required by syntax demands    a   1 if b else a   This piece of code leaves a unchanged when b turns to be False

User · Answer

You can use   print  1  2 and  only if condition true  or  in case condition is false     Just as well you can keep going like   print 1  2 and  aa  or   2  3  and  bb  or  cc     Real world example    gt  gt  gt  print   d item s found      count   count gt 1 and  s  or      1 item found   gt  gt  gt  count   2  gt  gt  gt  print   d item s found      count   count gt 1 and  s  or      2 items found

User · Answer

Python does not have a trailing if statement   There are two kinds of if in Python    if statement   if condition  statement if condition      block  if expression  introduced in Python 2 5   expression if true if condition else expression if false    And note  that both print a and b   a are statements  Only the a part is an expression  So if you write  print a if b else 0   it means  print  a if b else 0    and similarly when you write  x   a if b else 0   it means  x    a if b else 0    Now what would it print assign if there was no else clause  The print assignment is still there   And note  that if you don t want it to be there  you can always write the regular if statement on a single line  though it s less readable and there is really no reason to avoid the two-line variant

User · Answer

This can be done with string formatting  It works with the   notation as well as  format   and f-strings  new to 3 6   print   s     a if b else       or  print      format a if b else       or  print f  a if b else

User · Answer

For your case this works   a   b or 0   Edit  How does this work   In the question  b   True   So evaluating  b or 0   results in  True   which is assigned to a   If b    False   b or 0 would evaluate to the second operand 0 which would be assigned to a

User · Answer

You re simply overcomplicating   if b     print a

User · Answer

Since 2 5 you can use equivalent of C   s          ternary conditional operator and the syntax is    on true  if  expression  else  on false    So your example is fine  but you ve to simply add else  like   print a if b else

User · Answer

Try this   It might help you  a 100 b True  if b     print a

User · Answer

hmmm  you can do it with a list comprehension  This would only make sense if you had a real range   but it does do the job   print  a for i in range 0 1  if b     or using just those two variables   print  a for a in range a a 1  if b

User · Answer

The  else  statement is mandatory  You can do stuff like this     gt  gt  gt  b   True  gt  gt  gt  a   1 if b else None  gt  gt  gt  a 1  gt  gt  gt  b   False  gt  gt  gt  a   1 if b else None  gt  gt  gt  a  gt  gt  gt     EDIT   Or  depending of your needs  you may try    gt  gt  gt  if b  print a

User · Answer

You always need an else in an inline if   a   1 if b else 0   But an easier way to do it would be a   int b

[python] How to write inline if statement for print?

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