change values in column pandas code example

Example 1: replace column values pandas

df['column'] = df['column'].str.replace(',','-')
df

Example 2: replacing values in pandas dataframe

df['coloum'] = df['coloum'].replace(['value_1','valu_2'],'new_value')

Example 3: python replace pandas df elements if they aren't in a list

# Basic syntax:
df.loc[~df['col_name'].isin(list_of_allowed_vals), "col_name"] = "None"

# Example usage:
# Build example dataframe:
dataframe = pd.DataFrame(['ok','keep','wtf','ok'], columns=['col_name'])
print(dataframe)
  col_name
0       ok
1     keep
2      wtf
3       ok

list_of_allowed_vals = ['ok', 'keep'] # Define list of elements to keep

# Replace values that aren't the list of allowed values with "None":
dataframe.loc[~dataframe['col_name'].isin(list_of_allowed_vals), "col_name"] = "None"
print(dataframe)
  col_name
0       ok
1     keep
2     None
3       ok

# If you want to do this on all columns of the dataframe, run:
dataframe[~dataframe.isin(list_of_allowed_vals)] = "None"

Example 4: how to change column name in pandas

print(df.rename(columns={'A': 'a', 'C': 'c'}))
#         a   B   c
# ONE    11  12  13
# TWO    21  22  23
# THREE  31  32  33

Example 5: replace values of pandas column

df.loc[df['column'] == 'column_value', 'column'] = 'new_column_value'