I have the following command:
df1['parent'] = df1['x'].map(lambda x: x.split('by')[1])
and I get:
IndexError: list index out of range
For some of the values in the column,there is nothing after the "by", how I can do something like: if there is nothing after by then write ""
Use str.split with indexing with str which return NaN if no value, so then add fillna:
df1 = pd.DataFrame({'x':['ddbytrr','df']})
print (df1)
x
0 ddbytrr
1 df
df1['parent'] = df1['x'].str.split('by').str[1].fillna('')
print (df1)
x parent
0 ddbytrr trr
1 df
Solution with map and if-else, but it only works if no NaNs values in column:
df1['parent'] = df1['x'].map(lambda x: x.split('by')[1] if len(x.split('by')) > 1 else '')
print (df1)
x parent
0 ddbytrr trr
1 df
What is same as numpy.where solution:
splitted = df1['x'].str.split('by')
df1['parent'] = np.where(splitted.str.len() > 1, splitted.str[1], '')
print (df1)
x parent
0 ddbytrr trr
1 df
