CODEWITHSUNDEEP
pythonpandas
duckworthd
duckworthd

Reputation: 15217

Quickly applying string operations in a pandas DataFrame

Suppose I have a DataFrame with 100k rows and a column name. I would like to split this name into first and last name as efficiently as possibly. My current method is,

def splitName(name):
  return pandas.Series(name.split()[0:2])

df[['first', 'last']] = df.apply(lambda x: splitName(x['name']), axis=1)

Unfortunately, DataFrame.apply is really, really slow. Is there anything I can do to make this string operation nearly as fast as a numpy operation?

Thanks!

Upvotes: 12

Views: 15726

Answers (1)

Wes McKinney
Wes McKinney

Reputation: 105591

Try (requires pandas >= 0.8.1):

splits = x['name'].split()
df['first'] = splits.str[0]
df['last'] = splits.str[1]

Upvotes: 23

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