Python debugger PDB nested for loops SyntaxError: invalid syntax(, line 1)

Question

When I run a script with PDB, I find that I have to put for loops into one line to run correctly. When I try to nest for loops as shown below, I get a SyntaxError. How can I run nested for loops??

(pdb) for input in range(20): print input*2
0
2
4
...
36
38

(pdb) for input in range(20): for output in range(10): print input*2
*** SyntaxError: invalid syntax(<stdin>, line 1)

this may help you http://stackoverflow.com/questions/5967241/how-to-execute-multi-line-statements-within-pythons-own-debugger-pdb — Mauro Baraldi, Aug 06 '14 at 21:39

score 2 · Answer 1 · answered Aug 06 '14 at 22:04

2

This does not have to do with pdb, but is just python (this fails in the normal python repl).

The grammar for a for statement is defined as:

for_stmt ::=  "for" target_list "in" expression_list ":" suite
              ["else" ":" suite]

where suite is either a list of simple statements or a newline and a list of statements. the for statment is a compound statement so it cannot be inlined like that.

answered Aug 06 '14 at 22:04

Joe Jevnik

81
1
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And I can't do newlines in PDB, so how do I iterate an operation over two variables in PDB? – user278016 Aug 06 '14 at 22:41
run `help commands` in pdb, this is most likely the command you are looking for. – Joe Jevnik Aug 07 '14 at 14:14

Python debugger PDB nested for loops SyntaxError: invalid syntax(, line 1)

1 Answers1