title: Combining columns for each row in a data frame
body: <p>I would like to combine two columns: Column 1 + Column 2 and that for each row individually. Unfortunately it didn't work for me. How do i solve this?</p>
  <pre><code>import pandas as pd
  import numpy as np
  
  d = {'Nameid': [1, 2, 3, 1], 'Name': ['Michael', 'Max', 'Susan', 'Michael'], 'Project': ['S455', 'G874', 'B7445', 'Z874']}
  df = pd.DataFrame(data=d)
  display(df.head(10))
  df['Dataframe']='df'
  </code></pre>
  <p><a href="https://i.stack.imgur.com/UOEUa.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/UOEUa.png" alt="enter image description here" /></a></p>
  <pre><code>d2 = {'Nameid': [4, 2, 5, 1], 'Name': ['Petrova', 'Michael', 'Mike', 'Gandalf'], 'Project': ['Z845', 'Q985', 'P512', 'Y541']}
  df2 = pd.DataFrame(data=d2)
  display(df2.head(10))
  df2['Dataframe']='df2'
  </code></pre>
  <p><a href="https://i.stack.imgur.com/sw8Li.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/sw8Li.png" alt="enter image description here" /></a></p>
  <hr />
  <p>What I tried</p>
  <pre><code>df_merged = pd.concat([df,df2])
  df_merged.head(10)
  </code></pre>
  <p><a href="https://i.stack.imgur.com/NaCup.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/NaCup.png" alt="enter image description here" /></a></p>
  <pre><code>df3 = pd.concat([df,df2])
  df3['unique_string'] = df['Nameid'].astype(str) + df['Dataframe'].astype(str) 
  
  
  df3.head(10)
  </code></pre>
  <p><a href="https://i.stack.imgur.com/SfVZo.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/SfVZo.png" alt="enter image description here" /></a></p>
  <p>As you can see, he didn't combine every row. He probably only has the first combined with all of them. How can I combine the two columns row by row?</p>
  <p>What I want</p>
  <p><a href="https://i.stack.imgur.com/f65Kc.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/f65Kc.png" alt="enter image description here" /></a></p>