Jane Lee - 7 months ago 41

Python Question

I am having issue plotting two dataframs. One has 20711 entries, the other is 20710 entries. I am using plot(x,y) to plot like this:

`import pandas as pd`

import csv

import matplotlib.pyplot as plt

fig1 = plt.figure(figsize= (10,10))

ax = fig1.add_subplot(111)

ax.plot(X, Y)

Both are dataframes that were pulled from a csv. that have this structure:

`print(X)`

0 -2.343060

1 -2.445431

2 -2.335754

3 -2.478535

4 -2.527026

print(Y)

0 0.026940

1 -0.075431

2 0.024246

3 -0.118535

4 -0.167026

5 -0.145475

I keep getting error:

`ValueError: x and y must have same first dimension`

How do I fix it so that it ignores the last entry?

Answer

Well if you can just ditch the last value of Y then the following should work, assuming you have the index in your dataframe too, that is, your csv looks like this:

```
0,-2.343060
1,-2.445431
2,-2.335754
3,-2.478535
4,-2.527026
```

and you loaded it like `X=pandas.read_csv('x.csv')`

, then

```
ax.plot(X.as_matrix().T[1], Y.as_matrix().T[1][:-1])
```

should work.

As you mentioned in your comment the overlap varies:

```
ax.plot(X.as_matrix().T[1], Y.as_matrix().T[1][:len(x)])
```

Source (Stackoverflow)