# ds1000 / 273

- taskset: [ds1000](https://harnessreport.com/tasks/ds1000.md)
- difficulty: 
- category: 
- language: 
- runnable from the site: no
- agent timeout: 1800s

## Results by harness

_none yet_

## Instruction

```
# 273: DS-1000 Task

## Prompt
Problem:
I do know some posts are quite similar to my question but none of them succeded in giving me the correct answer. I want, for each row of a pandas dataframe, to perform the sum of values taken from several columns. As the number of columns tends to vary, I want this sum to be performed from a list of columns.
At the moment my code looks like this:
df['Sum'] = df['Col A'] + df['Col E'] + df['Col Z']


I want it to be something like :
df['Sum'] = sum(list_of_my_columns)


or
df[list_of_my_columns].sum(axis=1)


But both of them return an error. Might be because my list isn't properly created? This is how I did it:
list_of_my_columns = [df['Col A'], df['Col E'], df['Col Z']]


But this doesn't seem to work... Any ideas ? Thank you !
A:
<code>
import pandas as pd
import numpy as np


np.random.seed(10)
data = {}
for i in [chr(x) for x in range(65,91)]:
    data['Col '+i] = np.random.randint(1,100,10)
df = pd.DataFrame(data)
list_of_my_columns = ['Col A', 'Col E', 'Col Z']
</code>
df = ... # put solution in this variable
BEGIN SOLUTION
<code>

## What to do
- Edit `solution/solution.py` so the code passes the DS-1000 tests.
- Do not access the internet or install new packages; required libraries are preinstalled in the Docker image.
- Run tests locally via `bash tests/test.sh`.

## Notes
- Keep the variable names/signatures implied by the prompt/code_context.
- The evaluator uses the original DS-1000 `code_context` (`test_execution` / `test_string`).
```
---
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