I have a dataframe with a column Fib, I am trying to grab a substring from it:
Could anyone please tell me why this code does not work:
df['new'] = df['Fib'].apply(lambda x:x.str[2:10])
AttributeError: 'str' object has no attribute 'str'
But if i do this, it will work:
df['new_col'] = df['Fib'].astype(str).str[2:10]
I am trying to solve the above problem with apply+lambda just to get some experience with it. Thank you
The problem in your code is that the lambda function you apply along the rows of your series will be receiving a string as it appears. Here's an example to illustrate this:
df = pd.DataFrame({'num':[1,4,2], 'alpha':['apple','orange','peach']})
df['alpha'].apply(lambda x:type(x))
<class 'str'>
<class 'str'>
<class 'str'>
Note that Series.str methods are only for Series, as clearly stated in the documentation:
Vectorized string functions for Series and Index
So for your example you should avoid using apply. Instead do:
df['alpha'].str[2:10]
0 ple
1 ange
2 ach
Name: alpha, dtype: object
If what you want is to use apply instead as you mention, you simply need lambda x: x[2:10] as you are directly slicing the string:
df['alpha'].apply(lambda x: x[2:10])
0 ple
1 ange
2 ach
Name: alpha, dtype: object
df['new'] = df['Fib'].apply(lambda x:x[2:10])don't usestrinside the lambdaapply. Use slice instead