﻿ Pandas: Add leading zeros to the character column in a pandas series and makes the length of the field to 8 digit - w3resource

# Pandas: Add leading zeros to the character column in a pandas series and makes the length of the field to 8 digit

## Pandas: String and Regular Expression Exercise-4 with Solution

Write a Pandas program to add leading zeros to the character column in a pandas series and makes the length of the field to 8 digit.

Sample Solution:

Python Code :

``````import pandas as pd
nums = {'amount': ['10', '250', '3000', '40000', '500000']}
print("Original dataframe:")
df = pd.DataFrame(nums)
print(df)
df['amount'] = list(map(lambda x: x.zfill(10), df['amount']))
print(df)
``````

Sample Output:

```Original dataframe:
amount
0      10
1     250
2    3000
3   40000
4  500000

amount
0  0000000010
1  0000000250
2  0000003000
3  0000040000
4  0000500000
```

Python Code Editor:

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## Python: Tips of the Day

Python: Cache results with decorators

There is a great way to cache functions with decorators in Python. Caching will help save time and precious resources when there is an expensive function at hand.

Implementation is easy, just import lru_cache from functools library and decorate your function using @lru_cache.

```from functools import lru_cache

@lru_cache(maxsize=None)
def fibo(a):
if a <= 1:
return a
else:
return fibo(a-1) + fibo(a-2)

for i in range(20):
print(fibo(i), end="|")

print("\n\n", fibo.cache_info())
```

Output:

```0|1|1|2|3|5|8|13|21|34|55|89|144|233|377|610|987|1597|2584|4181|

CacheInfo(hits=36, misses=20, maxsize=None, currsize=20)```