In this article, we will discuss how to create an empty pandas DataFrame with just column names.
Table of Contents
Before getting started, let’s import the pandas and NumPy library which we will be using in this tutorial.
# importing libraries import pandas as pd import numpy as np
Using pandas DataFrame
pandas.DataFrame is the method to create DataFrame easily. In order to create an empty DataFrame, all we need to do is pass the names of the columns required. Let’s look at the example below.
import pandas as pd # create an empty with 4 columns df = pd.DataFrame(columns=['col_' + str(i) for i in range(4)]) print(df)
Output
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Empty DataFrame Columns: [col_0, col_1, col_2, col_3] Index: []
We have an empty DataFrame with all the columns specified. Let’s look at the dtypes of all the columns.
# check dtypes print (df.dtypes)
Output
col_0 object col_1 object col_2 object col_3 object dtype: object
By default, pandas will create columns with object dtype. In case we want to initiate it with something else, we will need to define it using empty pandas.Series as below.
import pandas as pd # create empty DataFrame with specific column types df = pd.DataFrame({'col_0': pd.Series(dtype='str'), 'col_1': pd.Series(dtype='int'), 'col_2': pd.Series(dtype='str'), 'col_3': pd.Series(dtype='float')}) print (df) print(df.dtypes)
Output
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Empty DataFrame Columns: [col_0, col_1, col_2, col_3] Index: [] col_0 object col_1 int64 col_2 object col_3 float64 dtype: object
Here you go, we have an empty DataFrame with the columns having a specific dtype.
Using Numpy
We can create an empty DataFrame using the numpy.empty method, which creates an empty object that can be fed into the pandas.DataFrame function. Here also we can define the custom dtypes as required. Let’s look at the implementation below.
import pandas as pd import numpy as np # define dtypes dtypes = np.dtype( [ ("col_0", object), ("col_1", int), ("col_2", object), ("col_3", float) ] ) # create an empty DataFrame df = pd.DataFrame(np.empty(0, dtype=dtypes)) print (df) print(df.dtypes)
Output
Empty DataFrame Columns: [col_0, col_1, col_2, col_3] Index: [] col_0 object col_1 int64 col_2 object col_3 float64 dtype: object
This also yields a similar output as the above method.
Summary
In this article, we have discussed how to create an empty DataFrame with just column names.
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