pandas - Unbound local error: ("local variable referenced before assignment") -

import pandas pd, numpy np  d = [{'cabin': 'f g13'},{'cabin': 'a32 a45'},{'cabin': 'f23 f36'},{'cabin': 'b24'},{'cabin': nan}] df = pd.dataframe(d)  def deck_list(row):     if row['cabin']!=row['cabin']:         cabinid = 'none'     else:         cabinsubstr = row['cabin'].split(' ')         in cabinsubstr:             if i.find('f ') != -1:                 cabinid = i[0][0]                 break             if i.find('f ') == 0:                 cabinid = i[1][0]                 break            return cabinid  df['deck_id'] = df.apply(deck_list, axis=1) 

am missing something? i've written akin plenty of times , i've never gotten error maybe it's stupid?

another way write this, using vectorized string methods is:

import pandas pd import numpy np nan = np.nan df = pd.dataframe([{'cabin': 'f g13'},                    {'cabin': 'a32 a45'},                    {'cabin': 'f23 f36'},                    {'cabin': 'b24'},                    {'cabin': nan}])  cabin_parts = df['cabin'].str.split(' ', expand=true) conditions = [pd.isnull(df['cabin']),                df['cabin'].str.startswith('f').astype(bool),                ~df['cabin'].str.contains('f').astype(bool)] choices = [none,             cabin_parts[1].str[0],             cabin_parts[0].str[0]]  df['deck_id'] = np.select(conditions, choices) 

which yields

     cabin deck_id 0    f g13       g 1  a32 a45       2  f23 f36       f 3      b24       b 4      nan    none 

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alternatively, if understand cabin --> deck_id naming pattern correctly, perhaps

df['deck_id'] = df['cabin'].str.extract(r'(\d\d*)?\s*(\d\d+)', expand=true)[1].str[0] 

would suffice, since

in [86]: df['cabin'].str.extract(r'(\d\d*)?\s*(\d\d+)', expand=true) out[86]:       0    1 0    f  g13 1  a32  a45 2  f23  f36 3  nan  b24 4  nan  nan 

the regex pattern (\d\d*)?\s*(\d\d+) has following meaning:

(\d\d*)?     first capturing group: 0-or-1 (nondigit followed 0-or-more digits) \s*          0-or-more whitespace (\d\d+)      second capturing group: (nondigit followed 1-or-more digits)