Script to update IDs that triggered AttributeError: Can only use .str accessor with string values!

update_rosmap_ids.py

import synapseclient
import pandas as pd

# Backstory:  When Sample Master was first created, the Rush
# project IDs were used as the values for 'individualID'.
# But, projids weren't fully anonymous and so couldn't be used
# as individualID annotations.  Rush generated anonymized IDs
# with format R####### that are acceptable to use for
# (publicly-visible) annotations.  We are now using the
# Rush-generated values as individual IDs and keeping
# the project IDs in the projid variable.  Projids
# are still visible to folks who have signed the ROSMAP DUC.


syn = synapseclient.login()

# Get individualID (Rush-generated anonymized IDs)
rosmap_clin_entity = syn.get('syn3191087')
rosmap_clin_df = pd.read_csv(rosmap_clin_entity.path)
rosmap_id_df = rosmap_clin_df[['individualID', 'projid']]

# Get all ROSMAP records from Sample Master
rosmap_sm_table = syn.tableQuery("select * from syn18912660 where study = 'ROSMAP'")
rosmap_sm_df = rosmap_sm_table.asDataFrame()
rosmap_sm_cols = rosmap_sm_df.columns.values.tolist()
rosmap_sm_df['rowId'] = rosmap_sm_df.index

# Move the projids to the projid variable, then drop individualID
# so we can easily add the updated Rush-generated values in the next step
rosmap_sm_df['projid'] = rosmap_sm_df['individualID']
rosmap_sm_df.drop(columns=['individualID'], inplace=True)

# Merge IDs into Sample Master to add the
# Rush-generated anonymized IDs as the 'individualID' values
rosmap_sm_id_df = rosmap_id_df.reset_index().merge(rosmap_sm_df,
                                                   how='right',
                                                   on='projid').set_index('rowId')

# Prepare table to upload to Synapse by putting columns in expected order
rosmap_updated_ids_df = rosmap_sm_id_df[rosmap_sm_cols].copy()
# Recast projid as a string since that's what the Synapse table is expecting
rosmap_updated_ids_df['projid'] = rosmap_updated_ids_df['projid'].astype(str)

rosmap_updated_ids_df.loc[rosmap_updated_ids_df['individualID'].isna(), 'individualID'] = ''

# Create df of records where the projid did not have a corresponding 
# anonymized individualID so that we can contact Rush and request 
# data for these participants (or find out why they're missing)
no_id_df = rosmap_updated_ids_df[pd.isna(rosmap_updated_ids_df.individualID)]
affected_projids = no_id_df.projid.unique()
affected_projids.sort()
print(', '.join(affected_projids))

# ... and push back to Synapse
rosmap_updated_ids_df = syn.store(synapseclient.Table(rosmap_sm_table.tableId, rosmap_updated_ids_df))