﻿ Pandas: Get topmost n records within each group of a DataFrame - w3resource

# Pandas: Get topmost n records within each group of a DataFrame

## Pandas: DataFrame Exercise-61 with Solution

Write a Pandas program to get topmost n records within each group of a DataFrame.

Sample Solution :

Python Code :

``````import pandas as pd
d = {'col1': [1, 2, 3, 4, 7, 11], 'col2': [4, 5, 6, 9, 5, 0], 'col3': [7, 5, 8, 12, 1,11]}
df = pd.DataFrame(data=d)
print("Original DataFrame")
print(df)
print("\ntopmost n records within each group of a DataFrame:")
df1 = df.nlargest(3, 'col1')
print(df1)
df2 = df.nlargest(3, 'col2')
print(df2)
df3 = df.nlargest(3, 'col3')
print(df3)
``````

Sample Output:

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

topmost n records within each group of a DataFrame:
col1  col2  col3
5    11     0    11
4     7     5     1
3     4     9    12
col1  col2  col3
3     4     9    12
2     3     6     8
1     2     5     5
4     7     5     1
col1  col2  col3
3     4     9    12
5    11     0    11
2     3     6     8
```

Python-Pandas Code Editor:

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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]
```