﻿ Pandas: Extract year between 1800 to 2200 from the specified column of a given DataFrame - w3resource

# Pandas: Extract year between 1800 to 2200 from the specified column of a given DataFrame

## Pandas: String and Regular Expression Exercise-29 with Solution

Write a Pandas program to extract year between 1800 to 2200 from the specified column of a given DataFrame.

Sample Solution:

Python Code :

``````import pandas as pd
import re as re
pd.set_option('display.max_columns', 10)
df = pd.DataFrame({
'company_code': ['c0001','c0002','c0003', 'c0003', 'c0004'],
'year': ['year 1800','year 1700','year 2300', 'year 1900', 'year 2200']
})
print("Original DataFrame:")
print(df)
def find_year(text):
#line=re.findall(r"\b(18[0][0]|2[0-2][00])\b",text)
result = re.findall(r"\b(18[0-9]{2}|19[0-8][0-9]|199[0-9]|2[01][0-9]{2}|2200)\b",text)
return result
df['year_range']=df['year'].apply(lambda x: find_year(x))
print("\Extracting year between 1800 to 2200:")
print(df)
``````

Sample Output:

```Original DataFrame:
company_code       year
0        c0001  year 1800
1        c0002  year 1700
2        c0003  year 2300
3        c0003  year 1900
4        c0004  year 2200
\Extracting year between 1800 to 2200:
company_code       year year_range
0        c0001  year 1800     [1800]
1        c0002  year 1700         []
2        c0003  year 2300         []
3        c0003  year 1900     [1900]
4        c0004  year 2200     [2200]
```

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)```