Syntax error with Python one-liner

Question

python -c 'import sys; print "a"'

works, and

python -c 'for a in [1, 2, 3]: print a'

works, but

python -c 'import sys; for a in [1, 2, 3]: print a'

fails with

File "<string>", line 1
  import sys; for a in [1, 2, 3]: print a
                ^

Why?

---

EDIT My workaround:

python -c 'import sys; print "\n".join([1, 2, 3])'

(Luckily it worked for my real code too.)

Answer 1

You can only use ; to separate non-compound statements on a single line; the grammar makes no allowance for a non-compound statement and a compound statement separated by a semicolon.

The relevant grammar rules are as follows:

stmt: simple_stmt | compound_stmt
simple_stmt: small_stmt (';' small_stmt)* [';'] NEWLINE

The ; in the simple_stmt production is the only place where semicolons are allowed to separate statements. For further details, see the full Python grammar.

Answer 2

Not an answer to your exact question, but still may help someone. You can actually split the command line in shell.

sh/bash/etc:

python -c 'import sys
for a in [1, 2, 3]: print a'

Windows cmd (C:\> and 'More?' are cmd prompts, don't enter those):

C:\>python -c import sys^
More?
More? for a in [1, 2, 3]: print a

Added in 2021: For some reason the cmd version above does not work on my current Windows 10 environment. Seems like w/o quotes Python interpreter truncates the command at first space. This variant still works:

C:\>python -c ^
More? "import sys^
More? 
More? for a in [1, 2, 3]: print a

Please note, that you need to press ENTER immediately after the caret (^) symbol. Also please note the double quote on the first continuation line in the last example.