import csv
# read rows
rows = []
with open('file.csv') as csvfile:
reader = csv.DictReader(csvfile, delimiter=',')
for row in reader:
rows.append(row)
# add the value
for row in rows:
row["Balance"] = float(row["Balance"]) + 10
# write csv back
with open("new.csv", "w", newline='') as outfile:
writer = csv.DictWriter(outfile, fieldnames=list(rows[0]))
writer.writeheader()
writer.writerows(rows)
I am also adding pandas way, maybe you use it later.
import pandas as pd
df = pd.read_csv("file.csv", index_col=0, delimiter = ",")
df["Balance"] += 10
df.to_csv("new.csv", sep=',')