When debugging in PHP, I frequently find it useful to simply stick a var_dump() in my code to show me what a variable is, what its value is, and the same for anything that it contains.
What is a good Python equivalent for this?
When debugging in PHP, I frequently find it useful to simply stick a var_dump() in my code to show me what a variable is, what its value is, and the same for anything that it contains.
What is a good Python equivalent for this?
To display a value nicely, you can use the pprint module. The easiest way to dump all variables with it is to do
from pprint import pprint
pprint(globals())
pprint(locals())
If you are running in CGI, a useful debugging feature is the cgitb module, which displays the value of local variables as part of the traceback.
PHP's var_export() usually shows a serialized version of the object that can be exec()'d to re-create the object. The closest thing to that in Python is repr()
"For many types, this function makes an attempt to return a string that would yield an object with the same value when passed to eval() [...]"
So I have taken the answers from this question and another question and came up below. I suspect this is not pythonic enough for most people, but I really wanted something that let me get a deep representation of the values some unknown variable has. I would appreciate any suggestions about how I can improve this or achieve the same behavior easier.
def dump(obj):
'''return a printable representation of an object for debugging'''
newobj=obj
if '__dict__' in dir(obj):
newobj=obj.__dict__
if ' object at ' in str(obj) and not newobj.has_key('__type__'):
newobj['__type__']=str(obj)
for attr in newobj:
newobj[attr]=dump(newobj[attr])
return newobj
Here is the usage
class stdClass(object): pass
obj=stdClass()
obj.int=1
obj.tup=(1,2,3,4)
obj.dict={'a':1,'b':2, 'c':3, 'more':{'z':26,'y':25}}
obj.list=[1,2,3,'a','b','c',[1,2,3,4]]
obj.subObj=stdClass()
obj.subObj.value='foobar'
from pprint import pprint
pprint(dump(obj))
and the results.
{'__type__': '<__main__.stdClass object at 0x2b126000b890>',
'dict': {'a': 1, 'c': 3, 'b': 2, 'more': {'y': 25, 'z': 26}},
'int': 1,
'list': [1, 2, 3, 'a', 'b', 'c', [1, 2, 3, 4]],
'subObj': {'__type__': '<__main__.stdClass object at 0x2b126000b8d0>',
'value': 'foobar'},
'tup': (1, 2, 3, 4)}