Extract all capital words from Dataframe in Pandas

In this article, we are to discuss various methods to extract capital words from a dataframe in the pandas module. Below is the dataframe which is going to be used to depict various approaches:

Python3

# Import pandas library
import pandas

# Create dataset
data = [['tom', 'DATAFRAME', '200.00'],
        ['PANDAS', 15, 3.14],
        ['r2j', 14, 'PYTHON']]

# Create the pandas DataFrame
df = pandas.DataFrame(data)

# Display dataframe
df

Output:

Method #1: Using ord() method in an explicit function

Create an explicit function to check if the string argument passed contains all capital characters or not. In the function check if each character is a capital letter or not by using their ASCII value. Now use that explicit function on each element of the dataframe to identify capital words and display them.

Python3

# Import pandas library
import pandas


# explicit function to check if string
# contains only uppercase characters
def findCap(s):
    for ele in str(s):
        if ord(ele) < 65 or ord(ele) > 90:
            return 0
    return 1


# Create dataset
data = [['tom', 'DATAFRAME', '200.00'],
        ['PANDAS', 15, 3.14],
        ['r2j', 14, 'PYTHON']]

# Create the pandas DataFrame
df = pandas.DataFrame(data)


# access each element in
# the dataframe
for i in range(df.shape[1]):
    for ele in df[i]:

        # call explicit function
        if findCap(ele):
            print(ele)

Output:

PANDAS
DATAFRAME
PYTHON

Method #2: Using str() and isupper() methods

Access each element of the dataframe and convert each element into a string using str(), after that apply isupper() method on each element. Extract the capital words from the dataframe and display them.

Python3

# Import pandas library
import pandas


# Create dataset
data = [['tom', 'DATAFRAME', '200.00'],
        ['PANDAS', 15, 3.14],
        ['r2j', 14, 'PYTHON']]

# Create the pandas DataFrame
df = pandas.DataFrame(data)


# access each element in the dataframe
for i in range(df.shape[1]):
   for ele in df[i]:

       # use isupper()
       if str(ele).isupper():
            print(ele)

Output:

PANDAS
DATAFRAME
PYTHON

Method #3: Using str() method and regex module

Access each element of the dataframe and convert each element into a string using str(), after that apply the regex to extract the capital words from the dataframe and display them.

Python3

# Import required modules
import re
import pandas


# Create dataset
data = [['tom', 'DATAFRAME', '200.00'],
        ['PANDAS', 15, 3.14],
        ['r2j', 14, 'PYTHON']]

# Create the pandas DataFrame
df = pandas.DataFrame(data)


# access each element in the dataframe
for i in range(df.shape[1]):
   for ele in df[i]:
        if bool(re.match(r'\w*[A-Z]\w*', str(ele))):
              print(ele)

Output:

PANDAS
DATAFRAME
PYTHON

Time Complexity: O(n*n)
Auxiliary Space: O(n), where n is length of list.