Data-frame

Data-frame

Data-frame via pandas is very useful format for working with dataset, its structure is two-dimensional size-mutable, potentially heterogeneous tabular data structure with labeled axes (rows and columns). The following codes create a data-frame from a dictionary.

var={"A": [1,2,0], "B": [2,3,4]}
df= pd.DataFrame(data=var,index=['A', 'Z', 'C'])

The label column can be easily changed:

raw_data = {'population': [ 1015.0, 1129.0, 333.0,  515.0],'median_income': [ 1.5, 1.8,  1.7,  3.2]}
df=pd.DataFrame(raw_data, columns = ['population', 'median_income'])

In some circumstances, it is better to consider the time of collecting data as index, the following script changes the data format to the time format and save it as index.

df = df.set_index(pd.to_datetime(['2019-04-01','2019-05-04','2019-06-01','2019-07-02']))

To create an empty data-frame, run the following

df1=pd.DataFrame(columns = ['population', 'median_income'])
df2=pd.DataFrame()

Dimension of data-frame is 2 which can be seen via .ndim, the number of rows and columns can be obtained using .shape.

df.ndim
df.shape
df.shape[0]
df.shape[1]