How can I keep leading zeros in a column, when I export to CSV?
This is an excel problem as @EdChum suggested. You'll want to wrap your column in =""
with apply('="{}".format)
. This will tell excel to treat the entry as a formula that returns the text within quotes. That text will be your values with leading zeros.
Consider the following example.
df = pd.DataFrame(dict(A=['001', '002']))
df.A = df.A.apply('="{}"'.format)
df.to_excel('test_leading_zeros.xlsx')
This may not be directly relevant to the question but if the data is read from external sources via pandas.read_csv()
or pandas.read_excel()
, then we could specify converters
for relevant columns using str
.
For example,
import pandas as pd
df = pd.read_excel(
'./myexcel.xlsx',
converters={
"serialno": str, # Ensure serialno is read as string, maintaining leading 0's
"location": lambda x: '-' if x=='' else str(x),
}
df1 = pd.read_excel(
'./mycsv.csv',
converters={
"serialno": str, # Ensure serialno is read as string, maintaining leading 0's
"location": lambda x: '-' if x=='' else str(x),
}
When the data is saved to Excel or CSV files, the leading 0's are maintained.
The most simple solution is to just add dtype=str
while reading txt
or csv
file in Pandas:
df = pd.read_csv(r'C:\my_folder\my_file.csv', dtype=str)