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Introduction

Provide a Python to R translation of 30 essential Pandas methods introduced by Avi Chawla in The Only 30 Methods You Should Master To Become A Pandas Pro published on TowardsDataScience.

Set up

# enable python in RMarkdown
library(reticulate)

Create the dataframe in Python

Notice the index is set to be 2,3,1

import pandas as pd

df = pd.DataFrame([[6, 5,  10], 
                   [5, 8,  6], 
                   [3, 10, 4]], 
                  columns = ["col1", "col2", "col3"],
                  index = [2, 3, 1])

df.head()

   col1  col2  col3
2     6     5    10
3     5     8     6
1     3    10     4

Load the dataframe into R

Notice that the same index has been passed on to R

df <- py$df #access df as saved in Python(py) above

df |> head()

  col1 col2 col3
2    6    5   10
3    5    8    6
1    3   10    4

Method #28 Resetting the Index of a DataFrame

Python

In Python, we can use the reset_index() method to reset the index. But before that, let’s quickly review how we can choose values by index or by position (method #20 and #21).

df.loc[2] # we can use loc to get values with index

col1     6
col2     5
col3    10
Name: 2, dtype: int64

df.iloc[2] # we can use iloc to get values by position

col1     3
col2    10
col3     4
Name: 1, dtype: int64

df.reset_index(drop = True) #drop the old index

   col1  col2  col3
0     6     5    10
1     5     8     6
2     3    10     4

df

   col1  col2  col3
2     6     5    10
3     5     8     6
1     3    10     4

A bit more play with loc[] and iloc[] based on the newly set index

df.loc[1:2] # loc to get values with index

Empty DataFrame
Columns: [col1, col2, col3]
Index: []

df.iloc[[1,2],] # iloc to get values by position

   col1  col2  col3
3     5     8     6
1     3    10     4

R

In R, we can get values by positions using slice()

library(dplyr)

df |> slice(1:2) # choose the 1st and 2nd row

  col1 col2 col3
2    6    5   10
3    5    8    6

To choose rows by name, we need to tell R the row name using a list like this.

df[c('1','2'),]

  col1 col2 col3
1    3   10    4
2    6    5   10

To reset the row names in R

rownames(df) = 1:nrow(df)
df

  col1 col2 col3
1    6    5   10
2    5    8    6
3    3   10    4

sessionInfo()

R version 4.2.1 (2022-06-23 ucrt)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows 10 x64 (build 19045)

Matrix products: default

locale:
[1] LC_COLLATE=English_Australia.utf8  LC_CTYPE=English_Australia.utf8   
[3] LC_MONETARY=English_Australia.utf8 LC_NUMERIC=C                      
[5] LC_TIME=English_Australia.utf8    

attached base packages:
[1] stats     graphics  grDevices datasets  utils     methods   base     

other attached packages:
[1] dplyr_1.1.2     reticulate_1.30

loaded via a namespace (and not attached):
 [1] Rcpp_1.0.11       pillar_1.9.0      compiler_4.2.1    bslib_0.5.0      
 [5] later_1.3.1       jquerylib_0.1.4   git2r_0.32.0      workflowr_1.7.0  
 [9] tools_4.2.1       digest_0.6.33     lattice_0.20-45   jsonlite_1.8.7   
[13] evaluate_0.21     lifecycle_1.0.3   tibble_3.2.1      png_0.1-8        
[17] pkgconfig_2.0.3   rlang_1.1.1       Matrix_1.4-1      cli_3.6.1        
[21] rstudioapi_0.15.0 yaml_2.3.7        xfun_0.39         fastmap_1.1.1    
[25] withr_2.5.0       stringr_1.5.0     knitr_1.43        generics_0.1.3   
[29] fs_1.6.2          vctrs_0.6.3       sass_0.4.7        tidyselect_1.2.0 
[33] grid_4.2.1        rprojroot_2.0.3   here_1.0.1        glue_1.6.2       
[37] R6_2.5.1          fansi_1.0.4       rmarkdown_2.23    magrittr_2.0.3   
[41] whisker_0.4.1     promises_1.2.0.1  htmltools_0.5.5   renv_1.0.0       
[45] httpuv_1.6.11     utf8_1.2.3        stringi_1.7.12    cachem_1.0.8

Method #28 Resetting the Index of a DataFrame

Python to R Translation of 30 Essential Pandas Methods

Mena WANG

2022-12-02

Introduction

Set up

Create the dataframe in Python

Load the dataframe into R

Method #28 Resetting the Index of a DataFrame

Python

R