Interpolate return same ouput-CodePudding

There is the code:

x = np.array([2, 2.5, 3, 3.5, 3.75, 4, 4.5, 4.75, 5, 5.25, 5.5, 6])
y = np.array([5.197, 7.78, 11.14, 15.09, np.nan, 19.245, 23.11, np.nan, 26.25, np.nan, 28.6,30.3])
x.shape = (12, 1)
x.shape = (12, 1)
a = pd.DataFrame(x, y)
a.interpolate()
print(a)

And the output is the same, i have no idea what i do wrong.

5.197   2.00
7.780   2.50
11.140  3.00
15.090  3.50
NaN     3.75
19.245  4.00
23.110  4.50
NaN     4.75
26.250  5.00
NaN     5.25
28.600  5.50
30.300  6.00

CodePudding user response：

For new DataFrame is passed columns names in dictionary for avoid index from y, removed x.shape and output of interpolate is assigned back:

x = np.array([2, 2.5, 3, 3.5, 3.75, 4, 4.5, 4.75, 5, 5.25, 5.5, 6])
y = np.array([5.197, 7.78, 11.14, 15.09, np.nan, 19.245, 
              23.11, np.nan, 26.25, np.nan, 28.6,30.3])

a = pd.DataFrame({'a':x, 'b':y})
a = a.interpolate()
print(a)
       a        b
0   2.00   5.1970
1   2.50   7.7800
2   3.00  11.1400
3   3.50  15.0900
4   3.75  17.1675
5   4.00  19.2450
6   4.50  23.1100
7   4.75  24.6800
8   5.00  26.2500
9   5.25  27.4250
10  5.50  28.6000
11  6.00  30.3000