Python 2.7 and MySQL: grooming tuple

Question

I am self-taught in MySQL, Python and Linux based OS, and quite sure there must be a more elegant solution to the problem, or, at least, one that works along my lines. The code is taking data from the last 24 hours from a database and storing them to a .txt file to be handled further on. However, the output I am getting has additional symbols that are making further analysis troublesome - I want to know if there is a way to remove them.

My (relevant) code is:

    ...
    cur = db.cursor()
    cur.execute("SELECT * FROM Sens WHERE sdate > DATE_SUB(NOW(),INTERVAL 24 HOUR)")
    query = cur.fetchall()

    OutputFile = open("/root/Desktop/data.txt", "w")
    for i in range (0, len(query)):
        print>>OutputFile, query[i]
    ...

The reason I am using for loop is to have each row fetched printed in a newline. The result I get is as follows:

    ('0,01/24/16,12:41:49,45.185\r\r\n',)

The result I need is:

    0,01/24/16,12:41:49,45.185

Much appreciate the help, LZ.

As i see the results are a tuple first try query[i][0] and if there are still some chars left you can use re to help. — Gábor Erdős
– Gábor Erdős, Commented Jan 25, 2016 at 16:03

gtlambert · Accepted Answer · 2016-01-25 16:04:13Z

1

You could use:

for i in range (0, len(query)):
        print>>OutputFile, query[i][0].strip()

The [0] index selects the string from the tuple, and the strip() function removes the whitespace from the left and right hand side of the string.

answered Jan 25, 2016 at 16:04

gtlambert

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Comments

Daniel Roseman · Accepted Answer · 2016-01-25 16:10:52Z

0

For a start, you shouldn't ever be iterating over range(len(something)). Always iterate over the thing itself. Also, it's more idiomatic to use file.write to output, rather than pritnting.

From there, all you need to do is just output the first element in each item, with [0].

for q in query:
   OutputFile.write(q[0])

answered Jan 25, 2016 at 16:10

Daniel Roseman

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3 Comments

LunnaZ Over a year ago

I am always looking for quality programming tips, so thank you for them! Should I make q then a variable of the size of the length of query? like q = len(query)

Daniel Roseman Over a year ago

No, the whole point is that there is no need to get the length of the query. Just iterate over it.

LunnaZ Over a year ago

wow - i did not know that was even possible. yes, that works perfectly - thank you!!

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