return rows in a dataframe closest to a user-defined number

Question

I have a user defined number which I want to compare to a certain column of a dataframe.

I would like to return the rows of a dataframe which contain (in a certain

Answer 1

I think you can use the argsort method:

>>> df = pd.DataFrame({"A": 1e4*np.arange(100), "num": np.random.random(100)})
>>> x = 0.75
>>> df.ix[(df.num-x).abs().argsort()[:5]]
         A       num
66  660000  0.748261
92  920000  0.754911
59  590000  0.764449
27  270000  0.765633
82  820000  0.732601
>>> x = 0.33
>>> df.ix[(df.num-x).abs().argsort()[:5]]
         A       num
37  370000  0.327928
76  760000  0.327921
8    80000  0.326528
17  170000  0.334702
96  960000  0.324516

Answer 2

Kind of new to python and pandas but I would suggest this.

#make random df and get number
df = pd.DataFrame({'c1':0,'c2':np.random.random(100)})
x = .25
#find differences and sort
diff = df.c2.apply(lambda z: abs(x-z))
diff.sort()
#get the index for the 5 closest numbers
inds = diff.index[:5]

inds would then have the index locations from the original df for the 5 closest numbers. Hope this helps!