Python list | How to remove parenthesis,quotes and commas in my list?

Question

From my database, I'm returning a list to be displayed into my HTML page but my list has this unwanted symbols. I tried using split() function but it wont work. How can I remove those parenthesis,commas and quotes. Thanks for you help

The output is :

[('cenomar',), ('cedula',), ('Birth Certificate',), ('Clearance',)]

I want:

 [cenomar, cedula, Birth Certificate, Clearance]

Here is my python function:

 @app.route('/')
    def search():
        conn=psycopg2.connect("dbname='forms' user='postgres' password='everboy' 
       host='localhost' port='5432'")
       cur=conn.cursor()
       cur.execute("SELECT name from form")
       rows=cur.fetchall()
       print(rows)
       return render_template("form.html",rows=rows)

It seems that each element in you list is a tuple. You want to get the data inside the tuple right? — ICanKindOfCode
– ICanKindOfCode, Commented Dec 8, 2017 at 14:24

Ahmad · Accepted Answer · 2017-12-08 14:25:33Z

13

After This line: rows=cur.fetchall() add this line

rows=[i[0] for i in rows]

answered Dec 8, 2017 at 14:25

Ahmad

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Comments

N. Ivanov · Accepted Answer · 2017-12-08 14:37:35Z

1

An easy solution would be:

Input: ["('cenomar',)", "('cedula',)", "('Birth Certificate',)", "('Clearance',)"]

rows = ["('cenomar',)", "('cedula',)", "('Birth Certificate',)", "('Clearance',)"]
res = []
for r in rows:
    res.append(r[2:-3]) # this line ignores the beginning bracket and open quote and the closing bracket, comma, and close quote
print res

Output: ["cenomar", "cedula", "Birth Certificate", "Clearance"]

What happens is, you iterate over your list, and for each item you just cut off the things you don't need with the use of string manipulation ([n:m], where n is the starting character and m is the end character, in your case 2 indicates to start the string from the 3 character (ignoring the ( and ') and -3 indicates cut the string to 3 characters before the end of it (ignoring the ), ', and ,)).

EDIT 1

I noticed that your input may not be a string as my above answer suggests, if you have a tuple ("smth",) you can just simply get the 1st element. So the answer would change to:

Input: [('cenomar',), ('cedula',), ('Birth Certificate',), ('Clearance',)]

rows = [('cenomar',), ('cedula',), ('Birth Certificate',), ('Clearance',)]
res = []
for r in rows:
    res.append(r[0])
print res

Output: ["cenomar", "cedula", "Birth Certificate", "Clearance"]

The above implementation is written in long for ease of understanding, but as well can be translated into a shorter one liner like so:

rows = [i[0] for i in rows]

Hope this helps!

edited Dec 8, 2017 at 14:37

answered Dec 8, 2017 at 14:24

N. Ivanov

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2 Comments

ingofreyer Over a year ago

This is not the same input than the question had

N. Ivanov Over a year ago

@ingofreyer I just noticed that and have updated my answer. Thanks!

Spox · Accepted Answer · 2017-12-08 18:09:34Z

0

Try this one

l = [('cenomar',), ('cedula',), ('Birth Certificate',), ('Clearance',)]
b = []
for i in l:
    b.append(i[0])
print(b)

edited Dec 8, 2017 at 18:09

answered Dec 8, 2017 at 14:50

Spox

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