pandas iterate throw rows to see if value is alpha numeric

Question

so i have a df with a column that has various string values

col1

Hi
-Hi
+hi
=Hi

I would like to remove all of the non alpha numeric values in this column to this:

col1

Hi
Hi
hi
Hi

I know i can just do a str replace with those non alpha characters, but to future proof the script, I would like to use something like isalpha(). there might be different non alpha characters in the future.

jpp · Accepted Answer · 2018-09-11T15:30:55.390

1

You can use a list comprehension:

df['col1'] = [''.join([i for i in x if i.isalpha()]) for x in df['col1']]

print(df)

  col1
0   Hi
1   Hi
2   hi
3   Hi

If you have NaN or float values, remove them first by converting them to empty string:

df.loc[pd.to_numeric(df['col1'], errors='coerce').notnull(), 'col1'] = ''

edited Sep 11 '18 at 15:30

answered Sep 11 '18 at 15:19

jpp

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I get a TypeError: 'float' object is not iterable error. – skimchi1993 Sep 11 '18 at 15:24
@skimchi1993, See update. – jpp Sep 11 '18 at 15:31
so if i have HI-Hello. it would go to Hihello and not just Hi-Hello. I want to only remove it if the first character is alpha numeric like -Hi = Hi – skimchi1993 Sep 11 '18 at 15:35
1

@skimchi1993, But that wasn't your question. Don't change your question, please. I have rolled it back. If you have a new, different question, ask it separately. – jpp Sep 11 '18 at 15:37
got it! thats my fault. this does work so i will mark it as such. – skimchi1993 Sep 11 '18 at 15:40

Anna Iliukovich-Strakovskaia · Answer 2 · 2018-09-11T15:51:46.780

0

You can also use regular expressions:

df['col1'].str.findall(r'[a-zA-Z0-9]+').apply(lambda x: ''.join(x))

Output:

0  Hi
1  Hi
2  hi
3  Hi

edited Sep 11 '18 at 15:51

answered Sep 11 '18 at 15:23

Anna Iliukovich-Strakovskaia

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this removes non alpha characters even if it not in the front. so something like Hi-hello comes Hi – skimchi1993 Sep 11 '18 at 15:28
@skimchi1993 you are right. Updated. Now it's ok. – Anna Iliukovich-Strakovskaia Sep 11 '18 at 15:52

pandas iterate throw rows to see if value is alpha numeric

2 Answers2