Variable names get changed/curropted when saving 150,000 column pandas dataframe to pyreadstat

[KevinCrossDCL]

I'm working with a large dataset that has about 120,000 columns. When it's saved to pyreadstat it's messing up some of the variable names in the final SPSS. There's no issues in the dataframe before it's saved to pyreadstat. I can't share that data, but I can provide a script that will reproduce the problem with a dummy dataframe. If you set the number of columns at 100,000 it will produce an SPSS file with no issues, but soon as you go above that (not sure the exact number) it will start curropting the variable names in the saved SPSS. Try the below example with 120,000 or 150,000 and you will see what I mean. In SPSS when you scroll down to about column 10,000 you will see the issue with the names, you will also see 1,000's of V* variables at the end. I'm using pyreadstat version 1.2.7

import numpy as np
import pandas as pd
import pyreadstat

num_rows = 100
num_cols = 150000

data = np.random.randint(0, 101, size=(num_rows, num_cols))
df = pd.DataFrame(data, columns=[f'col_{i}' for i in range(num_cols)])
print(df.head())

pyreadstat.write_sav(df, f"{num_cols}_columns.zsav", compress=True)

I've found a fix for my requirements, and that is to split the dataframe into to chunks, save each to SPSS and then merge them together using SPSS syntax afterwards.

Setup Information:
How did you install pyreadstat? pip install
Platform (Windows 10 Enterprise 64 bit)
Python Version 3.10.11
Python Distribution (plain python)
Using Virtualenv or condaenv? No

[ofajardo]

Thanks for the reproducible example!. The issue with the column names an also be detected when reading the sav file with pyreadstat. This is most likely coming from the underlying C library Readstat, so we would need to file an issue over there and wait for it to be fixed, then it will be automatically fixed here as well once the code is updated.