Iterative loop to remove specific unwanted characters from a string

Question

I want to take the string 'APPLES_10_4' inside a dataframe and have it become 'APPLES'. The code I have come up with is below:

import pandas as pd
data = ['APPLES_10_4']

Name_Parameters = []
df = pd.DataFrame(data, columns = ['fruit'], index = ['count'])

    
def badletters(lastletter):
    badletters = ["1","2","3","4","5","6","7","8","9","_"]
    if lastletter in badletters:
        return True
    else:
        return False   

def stripe(variable):
    tempStrippedVariable = variable
    foundEndVariable = False
    while not foundEndVariable:
        lastletter = tempStrippedVariable [:-1]
        if badletters(lastletter):
            tempStrippedVariable = tempStrippedVariable [:-1]
        else:
            foundEndVariable = True
    strippedVariable = tempStrippedVariable
    return strippedVariable

for variable in df:
strippedVariable = stripe(str(variable))
prefixes = []
if strippedVariable not in prefixes:
    prefixes.append(strippedVariable)
print(df)

The output I am getting is the original dataframe with ['APPLES_10_4'] not the altered one that says ['APPLES'].

prefixes would be the whole dataframe full of other strings like 'mangoes_1_5' so the prefixes should be an array of fruit names without any of the "badletters" — Danger McGee, Aug 24 '20 at 18:17
The error is because the dataframe contains numbers, not just strings. — Barmar, Aug 24 '20 at 18:19
try just `for variable in df: print(variable)` and you'll see them. — Barmar, Aug 24 '20 at 18:21
So the problem is actually when you call the ```stripe``` function. ```for variable in df``` sets ```variable``` to an integer and not the test data that you are giving. — Rashid 'Lee' Ibrahim, Aug 24 '20 at 18:21

Barmar · Answer 1 · 2020-08-24T20:05:00.210

0

Some of the dataframe elements are integers, not strings. You can convert them to strings before calling stripe()

for variable in df:
    strippedVariable = stripe(str(variable))
    if strippedVariable not in prefixes:
        prefixes.append(strippedVariable)
print(prefixes)

Or you could just skip them.

for variable in df:
    if not isinstance(variable, str):
        continue
    strippedVariable = stripe(variable)
    if strippedVariable not in prefixes:
        prefixes.append(strippedVariable)
print(prefixes)

Another bug is in stripe():

lastletter = tempStrippedVariable [:-1]

should be

lastletter = tempStrippedVariable [-1]

You're setting lastletter to the entire string except the last letter.

But that whole function can be replaced with simply:

def stripe(variable):
    badletters = ["1","2","3","4","5","6","7","8","9","_"]
    return variable.rstrip(badletters)

Finally, for variable in df doesn't iterate over the dataframe contents, just the column names. See How to iterate over rows in a DataFrame in Pandas

for row in df.itertuples():
    variable = row[0]
    strippedVariable = stripe(variable)
    if strippedVariable not in prefixes:
        prefixes.append(strippedVariable)

edited Aug 24 '20 at 20:05

answered Aug 24 '20 at 18:23

Barmar

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I changed my code to what you did above but the output I get is the dataframe column name ['fruits'] not the changed string 'APPLES'. – Danger McGee Aug 24 '20 at 18:34
What do you see if you just do `print(variable)`? – Barmar Aug 24 '20 at 18:37
print(variable) outputs fruit – Danger McGee Aug 24 '20 at 18:39
The problem is the `for` loop, it's just iterating over the column names, not the data. – Barmar Aug 24 '20 at 18:39
I changed the column name to "fruit_10_4" to see if it was at least stripping away the 'badletters' but it isn't. So does that mean my stripe function doesn't work either. Along with my problem of iterating the column names – Danger McGee Aug 24 '20 at 18:41
Yeah, just try `print(stripe("fruit_10_4"))` and you'll see it doesn't work. – Barmar Aug 24 '20 at 18:44
Why not just `return variable.rstrip(badletters)`? – Barmar Aug 24 '20 at 18:46
Where would I add that? and yeah my stripe variable doesn't work. Not sure where i went wrong. – Danger McGee Aug 24 '20 at 19:12
Thank you so much! That fixed all my problems. – Danger McGee Aug 24 '20 at 20:20

Iterative loop to remove specific unwanted characters from a string

1 Answers1