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Python Program for Column to Row Transpose using Pandas

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  • Last Updated : 20 Jan, 2022
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Given an Input File, having columns Dept and Name, perform an operation to convert the column values to rows. Name contains pipe separated values that belong to a particular department identified by the column Dept.

Attached Dataset: emp_data

Examples:

Input:
dept, name
10, Vivek|John
20, Ritika|Shubham|Nitin
30, Vishakha|Ankit

Output:
dept, name
10, Vivek
10, John
20, Ritika
20, Shubham
20, Nitin
30, Vishakha
30, Ankit

Method 1: Pythonic Way

Python




# Reading Data From the text
# file
data = pd.read_csv(r'GFG.txt')
  
  
# create new data frame with 
# split value columns separates
# data into three columns as per
# separator mentioned
new = data["name"].str.split("|",expand = True
  
# making separate first name column
# from new data frame assign columnn
# values to dataframe new columns
# named as name*
data["Name1"] = new[0]
data["Name2"] = new[1]
data["Name3"] = new[2]
  
# Dropping old Name columns 
data.drop(columns =["name"], inplace = True
   
# create separate dataframes with two
# columns id,name
d_name1 = data[['dept','Name1']]
d_name2 = data[['dept','Name2']]
d_name3 = data[['dept','Name3']]
   
# perform concat/unions operation for
# vertical merging of dataframes
union_df=pd.concat([d_name1,d_name2,d_name3],ignore_index=True)
union_df.fillna('',inplace=True)
  
# concatenate values of series into one
# series "name"
union_df['name'] = union_df['Name1'].astype(str)+union_df['Name2'].astype(str)+union_df['Name3'].astype(str)
   
# drop column names
union_df.drop(['Name1','Name2','Name3'],axis=1,inplace=True)
  
# drop rows having empty values
final_df=union_df[union_df['name']!='']
  
# sort the dataframe data by dept values
final_df.sort_values('dept')

Output:
Column to Row Transpose using Pandas

Note: Shortcoming of above method is when there are more than 3 names separated by |

Method 2: Exploring Pandas

Python




emp_df = pd.read_csv(r'GFG.txt')
  
# split column data on basis of separator
# convert it into list using to_list
# stack method performs transpose operation
# to the data
emp_df1 = pd.DataFrame(emp_df.name.str.split('|').to_list(),
                       index = emp_df.dept).stack()
  
emp_df1 = emp_df1.reset_index([0, 'dept'])
emp_df1.columns =['Dept', 'Name']
  
emp_df1


Output:

Column to Row Transpose using Pandas

Method 3: The Pandas way: explode()

Python




df = pd.read_csv(r'GFG.txt')
  
# separate values using split()
# transpose is performed by explode 
# function explode function overcomes 
# the method1 shortcomings incase we
# have many columns we explode will do
# the task in no time and with no hassle
df1 = df.assign(name = df['name'].str.split('|')).explode('name')
df1

Output:
Column to Row Transpose using Pandas


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