for Loop multiple conditions

Question

I am trying to create a new variable (column) which values depend on the values of other variable, therefore I try to create a for loop with multiple conditions.

Here is the code that I tried:

ABC_Levels = []
for i in range(len(df_ABC)):
    if df_ABC.loc[i,'ABC']>=5.7:
        ABC_Levels.append('High')
    elif df_ABC.loc[i,'ABC']<5.4:
        ABC_Levels.append('Low')
    else:
        ABC_Levels.append('Intermediate')
ABC_Levels

It returns the following error:

KeyError: 0

The above exception was the direct cause of the following exception:

I guess that is something related with the first row because if I change the code for this one:

ABC_Levels = []
for i in range(len(df_ABC['ABC'])):
    if df_ABC.loc[i]>=5.7:
        ABC_Levels.append('High')
    elif df_ABC.loc[i]<5.4:
        ABC_Levels.append('Low')
    else:
        ABC_Levels.append('Intermediate')
ABC_Levels

It returns the value of the first row.

I'll appreciate any help

You're making us guess where the error is. Please edit the question and add the full error traceback message. — John Gordon, Apr 08 '23 at 01:00

Guru Stron · Accepted Answer · 2023-04-08T14:29:58.973

2

Not an answer (at least a full one), but personally I would try to use np.select instead of enumerating the dataframe. For example:

series = df_ABC['ABC']
conds = [series >= 5.7, series < 5.4]
choices = ['High', 'Low'] 
np.select(conds, choices, default='Intermediate').tolist()

UPD

Modification which worked for OP:

conditions = [ (df_ABC['ABC'] >= 5.7), (df_ABC['ABC'] <= 5.4) ] 
choices = ['High', 'Low'] 
df_ABC['ABC_expression'] = np.select(conditions, choices, default='Intermediate')
df_ABC

edited Apr 08 '23 at 14:29

answered Apr 08 '23 at 01:25

Guru Stron

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1

Hi all, it works using a Guru method, with a slight modification 'conditions = [ (df_ABC['ABC'] >= 5.7), (df_ABC['ABC'] <= 5.4) ] choices = ['High', 'Low'] df_ABC['ABC_expression'] = np.select(conditions, choices, default='Intermediate') df_ABC' Thank you every much for the help – Alex Apr 08 '23 at 14:18
1

Im new here, I marked as 'like' but never 'solved'. Now is marked as accepted!!! – Alex Apr 08 '23 at 15:00

for Loop multiple conditions

1 Answers1