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Pandas: Count number of columns of a DataFrame

Pandas: DataFrame Exercise-57 with Solution

Write a Pandas program to count number of columns of a DataFrame.

Sample Solution :

Python Code :

import pandas as pd
d = {'col1': [1, 2, 3, 4, 7], 'col2': [4, 5, 6, 9, 5], 'col3': [7, 8, 12, 1, 11]}
df = pd.DataFrame(data=d)
print("Original DataFrame")
print(df)
print("\nNumber of columns:")
print(len(df.columns))

Sample Output:

Original DataFrame
   col1  col2  col3
0     1     4     7
1     2     5     8
2     3     6    12
3     4     9     1
4     7     5    11

Number of columns:
3   

Python-Pandas Code Editor:

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Next: Write a Pandas program to select all columns, except one given column in a DataFrame.

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Python: Tips of the Day

Inserting if statements using conditional list comprehensions:

x = [1, 2, 3, 4, 5, 6]
result = []
for idx in range(len(x)):
    if x[idx] % 2 == 0:
        result.append(x[idx] * 2)
    else:
        result.append(x[idx])
result

Output:

[1, 4, 3, 8, 5, 12]
[(element * 2 if element % 2 == 0 else element) for element in x]

Output:

[1, 4, 3, 8, 5, 12]
[element * 2 for element in x if element % 2 == 0]

Output:

[4, 8, 12]