Answers.Body: <p>First of all, those are not fasta sequences. Fasta is a specific format, and requires a <code>&gt;</code> followed by a sequence identifier on one line and the one or more lines of sequence.</p>
  <p>Assuming you really have two files in the format you show, you can do:</p>
  <pre><code><span class="math-container">$ awk -F: '{ gsub(/ /,""); if(NR==FNR){bbone[$2]; next} for(b in bbone){print b$</span>2}}' file1 file2 
  GTCATGCTACGTGCTACGTGCTCGTCGCGCCGCTAGTGTAGCTGCTACTCCG
  ACTGCGTATGTCAGCATATAGACCGCCTCGCTAGTGTAGCTGCTACTCCG
  CGTAGCTAGCTAGCTCGTGTCGTGATGCTACTCCGCTAGTGTAGCTGCTACTCCG
  </code></pre>
  <p>The <code>gsub(/ /,&quot;&quot;);</code> just removes the extra space you have in <code>file1</code> after each <code>:</code>. If you also want to have the sequence names as you show, use:</p>
  <pre><code><span class="math-container">$ awk -F: '{ gsub(/ /,""); if(NR==FNR){bbone[$2]="Backbone"NR; next} for(b in bbone){print bbone[b]"+"$1":", b$</span>2}}' file1 file2 
  Backbone3+sequence_1: GTCATGCTACGTGCTACGTGCTCGTCGCGCCGCTAGTGTAGCTGCTACTCCG
  Backbone1+sequence_1: ACTGCGTATGTCAGCATATAGACCGCCTCGCTAGTGTAGCTGCTACTCCG
  Backbone2+sequence_1: CGTAGCTAGCTAGCTCGTGTCGTGATGCTACTCCGCTAGTGTAGCTGCTACTCCG
  </code></pre>
  <p>If you really need to do this in python for some reason, please edit your question and show us your python script so we have something to work on and expand. I really don't want to write a whole python program for something so trivial.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-11-20T10:58:13.010Z
Answers.LastActivityDate: 2020-11-20T11:18:28.540Z
Answers.LastEditDate: 2020-11-20T11:18:28.540Z
Answers.UserDisplayName: terdon
Body: <p>I have three backbone and i want to concatenate 70 sequence into these backbone.
  such like:
  fasta file 1:</p>
  <pre><code>Backbone1: ACTGCGTATGTCAGCATATAGACCGCCT
  Backbone2: CGTAGCTAGCTAGCTCGTGTCGTGATGCTACTC
  Backbone3: GTCATGCTACGTGCTACGTGCTCGTCGCGC
  </code></pre>
  <p>fasta file 2:</p>
  <pre><code>sequence_1:CGCTAGTGTAGCTGCTACTCCG
  </code></pre>
  <p>output sequence:</p>
  <pre><code>Backbone1+sequence_1: ACTGCGTATGTCAGCATATAGACCGCCTCGCTAGTGTAGCTGCTACTCCG
  Backbone2+sequence_1: CGTAGCTAGCTAGCTCGTGTCGTGATGCTACTCCGCTAGTGTAGCTGCTACTCCG
  Backbone3+sequence_1: GTCATGCTACGTGCTACGTGCTCGTCGCGCCGCTAGTGTAGCTGCTACTCCGs
  </code></pre>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2020-11-18T11:27:32.340Z
Comments.Text: Use Biopython's seqio
Comments.UserDisplayName: M__
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2020-11-18T12:19:54.423Z
Comments.Text: Can you give me some tips for writing codes?
Comments.UserDisplayName: xuechun zhang
Tags: <python><sequence-analysis><phylogenetics>
Title: How to concatenate two fasta sequences by py
ThreadText: # How to concatenate two fasta sequences by py
  
  (Asked by: username_0 on 2020-11-18)
  
  I have three backbone and i want to concatenate 70 sequence into these backbone.
  such like:
  fasta file 1:
  
  ```
  Backbone1: ACTGCGTATGTCAGCATATAGACCGCCT
  Backbone2: CGTAGCTAGCTAGCTCGTGTCGTGATGCTACTC
  Backbone3: GTCATGCTACGTGCTACGTGCTCGTCGCGC
  
  ```
  
  fasta file 2:
  
  ```
  sequence_1:CGCTAGTGTAGCTGCTACTCCG
  
  ```
  
  output sequence:
  
  ```
  Backbone1+sequence_1: ACTGCGTATGTCAGCATATAGACCGCCTCGCTAGTGTAGCTGCTACTCCG
  Backbone2+sequence_1: CGTAGCTAGCTAGCTCGTGTCGTGATGCTACTCCGCTAGTGTAGCTGCTACTCCG
  Backbone3+sequence_1: GTCATGCTACGTGCTACGTGCTCGTCGCGCCGCTAGTGTAGCTGCTACTCCGs
  
  ```
  
  **Tags:** python, sequence-analysis, phylogenetics
  
  > **Comments:**
  > **username_1**: Use Biopython's seqio  
  > **username_0**: Can you give me some tips for writing codes?  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_2 on 2020-11-20. Score: 1
  
  First of all, those are not fasta sequences. Fasta is a specific format, and requires a `>` followed by a sequence identifier on one line and the one or more lines of sequence.
  
  Assuming you really have two files in the format you show, you can do:
  
  ```
  $ awk -F: '{ gsub(/ /,""); if(NR==FNR){bbone[$2]; next} for(b in bbone){print b$2}}' file1 file2 
  GTCATGCTACGTGCTACGTGCTCGTCGCGCCGCTAGTGTAGCTGCTACTCCG
  ACTGCGTATGTCAGCATATAGACCGCCTCGCTAGTGTAGCTGCTACTCCG
  CGTAGCTAGCTAGCTCGTGTCGTGATGCTACTCCGCTAGTGTAGCTGCTACTCCG
  
  ```
  
  The `gsub(/ /,"");` just removes the extra space you have in `file1` after each `:`. If you also want to have the sequence names as you show, use:
  
  ```
  $ awk -F: '{ gsub(/ /,""); if(NR==FNR){bbone[$2]="Backbone"NR; next} for(b in bbone){print bbone[b]"+"$1":", b$2}}' file1 file2 
  Backbone3+sequence_1: GTCATGCTACGTGCTACGTGCTCGTCGCGCCGCTAGTGTAGCTGCTACTCCG
  Backbone1+sequence_1: ACTGCGTATGTCAGCATATAGACCGCCTCGCTAGTGTAGCTGCTACTCCG
  Backbone2+sequence_1: CGTAGCTAGCTAGCTCGTGTCGTGATGCTACTCCGCTAGTGTAGCTGCTACTCCG
  
  ```
  
  If you really need to do this in python for some reason, please edit your question and show us your python script so we have something to work on and expand. I really don't want to write a whole python program for something so trivial.
  
  
  ---
  
  