How to delete the last character of a string for all values in a Pandas Dataframe column?

Question

For example if this is my Dataframe (all values are str type):

    Random  Random2  Random3    
0   WNNX01  319845   6109100104 
1   WNNX01  319850   6205200002 
2   WNNX01  319865   6403990062 
3   WNNX01  319868   6109901000
4   WNNX01  319888   6204422000

How do I get rid of the last character in all values for "Random3" column? I want the result to look like this:

    Random  Random2  Random3    
0   WNNX01  319845   610910010  
1   WNNX01  319850   620520000  
2   WNNX01  319865   640399006  
3   WNNX01  319868   610990100
4   WNNX01  319888   620442200

This will work but it takes forever with millions of rows (been running for 15mins still not done):

for i in range(len(df)):
    df['Random3'][i] = df['Random3'][i][:-1]

What's a better way?

Answer 1

Try this. It would be more efficient than your code.

df['Random3'] = df['Random3'].astype(str).str.slice(start = 0, stop = -1)

Because the code makes 'Random3' column string, you can change the type using astype function as follows.

df['Random3'] = df['Random3'].astype(int)