check if variable is dataframe

when my function f is called with a variable I want to check if var is a pandas dataframe:

def f(var):
if var == pd.DataFrame():
    print "do stuff"

I guess the solution might be quite simple but even with

def f(var):
if var.values != None:
    print "do stuff"

I can't get it to work like expected.

---

isinstance, nothing else.

PEP8 says explicitly that isinstance is the preferred way to check types

Yes: if isinstance(obj, int):
No:  if type(obj) is type(1):

And don't even think about

if obj.__class__.__name__ = "MyInheritedClass":
    expect_problems_some_day()

isinstance handles inheritance (see Differences between isinstance() and type() in python). For example, it will tell you if a variable is a string (either str or unicode ), because they derive from basestring )

if isinstance(obj, basestring):
    i_am_string(obj)

---

使用内置的isinstance（）函数。

import pandas as pd

def f(var):
    if isinstance(var, pd.DataFrame):
        print "do stuff"

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