import pandas as pd

filenameStr = 'test.csv'
csv = pd.read_csv(filenameStr, encoding='ISO-8859-1', dtype=str, usecols=['project path', 'visits'])
print(len(csv))

project_path = csv['project path']
delete_index_list = []
for index, project in enumerate(project_path):
    if '#' in project:
        delete_index_list.append(index)

for index in delete_index_list:
    project_path[index] = project_path[index][:project_path[index].find('#')]

csv.to_csv('test.csv', index=False)
print(len(csv))