Why is “1.real” a syntax error but “1 .real” valid in Python?

by

I guess that the . is greedily parsed as part of a number, if possible, making it the float 1., instead of being part of the method call.

Spaces are not allowed around the decimal point, but you can have spaces before and after the . in a method call. If the number is followed by a space, the parse of the number is terminated, so it’s unambiguous.

Let’s look at the different cases and how they are parsed:

>>> 1.real    # parsed as (1.)real  -> missing '.'
>>> 1 .real   # parsed as (1).real  -> okay
>>> 1. real   # parsed as (1.)real  -> missing '.'
>>> 1 . real  # parsed as (1).real  -> okay
>>> 1..real   # parsed as (1.).real -> okay
>>> 1 ..real  # parsed as (1)..real -> one '.' too much
>>> 1.. real  # parsed as (1.).real -> okay
>>> 1 .. real # parsed as (1)..real -> one '.' too much

More Related Contents:

  1. Why is “1000000000000000 in range(1000000000000001)” so fast in Python 3?
  2. How to install pip with Python 3?
  3. unknown error: session deleted because of page crash from unknown error: cannot determine loading status from tab crashed with ChromeDriver Selenium
  4. How do I specify new lines on Python, when writing on files?
  5. How can I iterate through two lists in parallel?
  6. First non-null value per row from a list of Pandas columns
  7. Subclassing int in Python
  8. How do I change the range of the x-axis with datetimes in matplotlib?
  9. Find the most frequent number in a NumPy array
  10. Private members in Python
  11. Disable assertions in Python
  12. Why does the `is` operator behave differently in a script vs the REPL?
  13. APT command line interface-like yes/no input?
  14. How do I return a string from a regex match in python? [duplicate]
  15. How to solve “OSError: telling position disabled by next() call”
  16. Python datetime.utcnow() returning incorrect datetime
  17. Python unit test with base and sub class
  18. How do I run another script in Python without waiting for it to finish? [duplicate]
  19. Python check for integer input
  20. Python Threading inside a class
  21. Python Bool and int comparison and indexing on list with boolean values
  22. Duplicate items in legend in matplotlib?
  23. Python & Selenium: Difference between driver.implicitly_wait() and time.sleep()
  24. How would I check a string for a certain letter in Python?
  25. Environment Variables when script run by cron
  26. sklearn pipeline – how to apply different transformations on different columns
  27. Pytorch: how to add L1 regularizer to activations?
  28. win32: simulate a click without simulating mouse movement?
  29. How to use custom AdminSite class?
  30. PyQt: Always on top

Leave a Comment