pandas merge python
import pandas as pd
df1 = pd.DataFrame({'lkey': ['foo', 'bar', 'baz', 'foo'],
'value': [1, 2, 3, 5]})
df2 = pd.DataFrame({'rkey': ['foo', 'bar', 'baz', 'foo'],
'value': [5, 6, 7, 8]})
df1.merge(df2, left_on='lkey', right_on='rkey')merge in python
def merge(array, left_index, right_index, middle):
# Make copies of both arrays we're trying to merge
# The second parameter is non-inclusive, so we have to increase by 1
left_copy = array[left_index:middle + 1]
right_copy = array[middle+1:right_index+1]
# Initial values for variables that we use to keep
# track of where we are in each array
left_copy_index = 0
right_copy_index = 0
sorted_index = left_index
# Go through both copies until we run out of elements in one
while left_copy_index < len(left_copy) and right_copy_index < len(right_copy):
# If our left_copy has the smaller element, put it in the sorted
# part and then move forward in left_copy (by increasing the pointer)
if left_copy[left_copy_index] <= right_copy[right_copy_index]:
array[sorted_index] = left_copy[left_copy_index]
left_copy_index = left_copy_index + 1
# Opposite from above
else:
array[sorted_index] = right_copy[right_copy_index]
right_copy_index = right_copy_index + 1
# Regardless of where we got our element from
# move forward in the sorted part
sorted_index = sorted_index + 1
# We ran out of elements either in left_copy or right_copy
# so we will go through the remaining elements and add them
while left_copy_index < len(left_copy):
array[sorted_index] = left_copy[left_copy_index]
left_copy_index = left_copy_index + 1
sorted_index = sorted_index + 1
while right_copy_index < len(right_copy):
array[sorted_index] = right_copy[right_copy_index]
right_copy_index = right_copy_index + 1
sorted_index = sorted_index + 1Copyright © 2021 Codeinu
Forgot your account's password or having trouble logging into your Account? Don't worry, we'll help you to get back your account. Enter your email address and we'll send you a recovery link to reset your password. If you are experiencing problems resetting your password contact us
