Python Tips DataFrame & Dictionary

Pandas Dataframe Quick References

Given:

· Import pandas as pd

· Name=[‘Rob’, ‘John’, ‘Janice’]

· Age=[25,35,45]

Pointers:

1. How to define a dataframe from two equal size lists?

· df=pd.DataFrame({‘Name’: Name, ‘Age’:Age})

2. How to add another list to the dataframe df

· Label=[‘a’, ‘b’, ‘c’]

· df[‘label’]=label

3. How to get the shape of a Pandas dataframe?

· r, c = df.shape

4. How to add lists to a dataframe?

· Label=[‘a’, ‘b’, ‘c’]

· df[‘label’]=label

5. How to get value of a particular cell k?

· df[‘label’].values[k]

6. How to get a subset of a dataframe?

· Result_df = df[[‘label’, ‘size’]]

7. How to write a dataframe into a csv file?

· df.to_csv(file_path,header=None,Index=False)

8. How to find out values of a corresponding column based on a key column value?

a. Ex: find out age of Rob?

b. age_val= df[df[‘name’]== ‘Rob’].[‘age’].value[0]

Dictionary Tips:

9. How to build a disctionary from two lists

· Name=[‘Rob’, ‘John’, ‘Janice’]

· Age=[25,35,45]

Res=dict(zip(Name,Age))

10. Find what is the minimum age from a dictionary?

· Min(res.values())

11. Find what is the person’s name with minimum age?

· Min(res,key=res.get)