Pandas: Create a DataFrame from a Numpy array and specify the index column and column headers
Write a Pandas program to create a DataFrame from a Numpy array and specify the index column and column headers.
Sample Solution :
Python Code :
import pandas
import numpy
dtype = [('Column1','int32'), ('Column2','float32'), ('Column3','float32')]
values = numpy.zeros(15, dtype=dtype)
index = ['Index'+str(i) for i in range(1, len(values)+1)]
df = pandas.DataFrame(values, index=index)
print(df)
Sample Output:
Column1 Column2 Column3 Index1 0 0.0 0.0 Index2 0 0.0 0.0 Index3 0 0.0 0.0 Index4 0 0.0 0.0 Index5 0 0.0 0.0 Index6 0 0.0 0.0 Index7 0 0.0 0.0 Index8 0 0.0 0.0 Index9 0 0.0 0.0 Index10 0 0.0 0.0 Index11 0 0.0 0.0 Index12 0 0.0 0.0 Index13 0 0.0 0.0 Index14 0 0.0 0.0 Index15 0 0.0 0.0
Explanation:
dtype = [('Column1','int32'), ('Column2','float32'), ('Column3','float32')]: This code creates a Pandas DataFrame with 15 rows and 3 columns, named 'Column1', 'Column2', and 'Column3', respectively. The data type of the columns are set to be 'int32', 'float32', and 'float32', respectively.
values = numpy.zeros(15, dtype=dtype): This code creates a NumPy structured array with 15 rows and 3 fields using numpy.zeros function. numpy.zeros function initializes an array with zeros of given shape and data type.
index = ['Index'+str(i) for i in range(1, len(values)+1)]: This code sets the index for the DataFrame using a list comprehension. Here, the index is a list of strings starting from "Index1" to "Index15".
df = pandas.DataFrame(values, index=index): Finally, it creates the DataFrame using the Pandas DataFrame function with the values and index as parameters, and prints it using the print function.
Python-Pandas Code Editor:
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