lowercase

[bishoyisantosh]

def swap_whitespace_underscore(text):
result = []
for char in text:
if char == ' ':
result.append('')
elif char == '':
result.append(' ')
else:
result.append(char)
return ''.join(result)

Example usage

input_text = "dog_and cat"
output_text = swap_whitespace_underscore(input_text)
print("Input:", input_text)
print("Output:", output_text)