Add example to README

[mattcieslak]

Closes #6

[mattcieslak]

@smeisler could you check the pandas example?
And @tientong98 could you check R?
Both demonstrably worked with example data when I ran them, but do those idioms seem up to date?

[smeisler]

Pandas example looks good! I asked ChatGPT if there was any way to optimize it, and it returned the following, only slightly different:

import pandas as pd

# Load TSVs into DataFrames
fspost_data = pd.read_csv(
    "sub-01_atlas-Schaefer2018100Parcels7Networks_surfacestats.tsv", 
    sep="\t"
)

xcpd_reho = pd.read_csv(
    "sub-01_task-emotion_dir-LR_run-1_space-fsLR_seg-4S156Parcels_stat-reho_bold.tsv", 
    sep="\t"
)

# Wide to long conversion with efficient column renaming
xcpd_reho_long = xcpd_reho.melt(var_name="StructName", value_name="reho")
xcpd_reho_long["StructName"] = xcpd_reho_long["StructName"].radd("7Networks_")

merged_data = pd.merge(fspost_data, xcpd_reho_long, on="StructName")

[tien-tong]

The R example looks good to me.