One-line list comprehension if-else variants

Question

It s more about python list comprehension syntax  I ve got a list comprehension that produces list of odd numbers of a given range    x for x in range 1  10  if x   2    This makes a filter - I ve got a source list  where I remove even numbers  if x   2   I d like to use something like if-then-else here  Following code fails    gt  gt  gt   x for x in range 1  10  if x   2 else x   100    File   lt stdin gt    line 1      x for x in range 1  10  if x   2 else x   100                                             SyntaxError  invalid syntax   There is a python expression like if-else   1 if 0 is 0 else 3   How to use it inside a list comprehension

User · Answer

x if x   2 else x   100 for x in range 1  10

User · Answer

Just another solution  hope some one may like it    Using   False  True  Expression    gt  gt  gt  map lambda x   x 100  x  x   2    0   range 1 10    1  200  3  400  5  600  7  800  9   gt  gt  gt

User · Answer

x if y else z is the syntax for the expression you re returning for each element  Thus you need     x if x 2 else x 100 for x in range 1  10      The confusion arises from the fact you re using a filter in the first example  but not in the second  In the second example you re only mapping each value to another  using a ternary-operator expression   With a filter  you need     EXP for x in seq if COND     Without a filter you need     EXP for x in seq     and in your second example  the expression is a  complex  one  which happens to involve an if-else

User · Answer

I was able to do this   gt  gt  gt   x if x   2    0 else x   100 for x in range 1 10        1  200  3  400  5  600  7  800  9   gt  gt  gt

User · Answer

You can do that with list comprehension too   A   x 100  x  x   2    0  for x in range 1 11   print A

[python] One-line list comprehension: if-else variants

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