Issue
I want to create a new column in Pandas using a string sliced for another column in the dataframe.
For example.
Sample Value New_sample
AAB 23 A
BAB 25 B
Where New_sample
is a new column formed from a simple [:1]
slice of Sample
I've tried a number of things to no avail - I feel I'm missing something simple.
What's the most efficient way of doing this?
Solution
You can call the str
method and apply a slice, this will be much quicker than the other method as this is vectorised (thanks @unutbu):
df['New_Sample'] = df.Sample.str[:1]
You can also call a lambda function on the df but this will be slower on larger dataframes:
In [187]:
df['New_Sample'] = df.Sample.apply(lambda x: x[:1])
df
Out[187]:
Sample Value New_Sample
0 AAB 23 A
1 BAB 25 B
Answered By - EdChum
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