Python - pandas - apply - (Stackoverflow)

# date: 2025.02.22
# author: furas

# stackoverflow: [pandas - python definition that use try and except loop to create a column using the apply funtion - Stack Overflow](https://stackoverflow.com/questions/79446546/python-definition-that-use-try-and-except-loop-to-create-a-column-using-the-appl)

# doc: [pandas.DataFrame.apply — pandas 2.2.3 documentation](https://pandas.pydata.org/docs/reference/api/pandas.DataFrame.apply.html)

# --- version 1 - without `apply` ---

def date_difference(dataframe):
    dataframe['Permit Creation Date'] = dataframe['Permit Creation Date'].astype(str)
    dataframe['Issued Date'] = dataframe['Issued Date'].astype(str)
    dataframe['Issued Date'] = dataframe['Issued Date'].fillna(0)
    dataframe['Permit Creation Date'] = dataframe['Permit Creation Date'].fillna(0)

    results = []

    for x, y in zip(dataframe['Issued Date'], dataframe['Permit Creation Date']):
        try:
            d1 = datetime.datetime.strptime(x, "%Y-%m-%d")
            d2 = datetime.datetime.strptime(y, "%Y-%m-%d")
            print(abs(d1-d2).days)
            results.append(abs(d1-d2).days)
        except Exception as e:
            print(e.args)
            results.append(None)

    return results

type1['Date difference'] = date_difference(type1)  # without `apply`

# --- version 2 - without `apply` - some modifications outside function ---

dataframe['Permit Creation Date'] = dataframe['Permit Creation Date'].astype(str)
dataframe['Permit Creation Date'] = dataframe['Permit Creation Date'].fillna(0)

dataframe['Issued Date'] = dataframe['Issued Date'].astype(str)
dataframe['Issued Date'] = dataframe['Issued Date'].fillna(0)

def date_difference(dataframe):

    results = []

    for x, y in zip(dataframe['Issued Date'], dataframe['Permit Creation Date']):
        try:
            d1 = datetime.datetime.strptime(x, "%Y-%m-%d")
            d2 = datetime.datetime.strptime(y, "%Y-%m-%d")
            print(abs(d1-d2).days)
            results.append(abs(d1-d2).days)
        except Exception as e:
            print(e.args)
            results.append(None)

    return results

type1['Date difference'] = date_difference(type1)  # without `apply`

# --- version 3 - without `apply` - some modifications outside function - use `iterrows()` instead of `zip()` ---

dataframe['Permit Creation Date'] = dataframe['Permit Creation Date'].astype(str)
dataframe['Permit Creation Date'] = dataframe['Permit Creation Date'].fillna(0)

dataframe['Issued Date'] = dataframe['Issued Date'].astype(str)
dataframe['Issued Date'] = dataframe['Issued Date'].fillna(0)

def date_difference(dataframe):

    results = []

    for index, row in dataframe.iterrows():  # use `iterrows()`
        try:
            d1 = datetime.datetime.strptime(row['Issued Date'], "%Y-%m-%d")
            d2 = datetime.datetime.strptime(row['Permit Creation Date'], "%Y-%m-%d")
            print(abs(d1-d2).days)
            results.append(abs(d1-d2).days)
        except Exception as e:
            print(e.args)
            results.append(None)

    return results

type1['Date difference'] = date_difference(type1)  # without `apply`

# --- version 4 - apply ---

dataframe['Permit Creation Date'] = dataframe['Permit Creation Date'].astype(str)
dataframe['Permit Creation Date'] = dataframe['Permit Creation Date'].fillna(0)

dataframe['Issued Date'] = dataframe['Issued Date'].astype(str)
dataframe['Issued Date'] = dataframe['Issued Date'].fillna(0)

def apply_date_difference(row):  # it gets single row (Series)
    try:
        d1 = datetime.datetime.strptime(row['Issued Date'], "%Y-%m-%d")
        d2 = datetime.datetime.strptime(row['Permit Creation Date'], "%Y-%m-%d")
        print(abs(d1-d2).days)
        return abs(d1-d2).days
    except Exception as e:
        print(e.args)
        return None

type1['Date difference'] = type1.apply(date_difference)