Year: 2009

It’s all about printf() and String Formatting

Post author By masnun
Post date May 2, 2009

The printf() function was most probably introduced in C. The function, as most of the programmers know, prints formatted string according to a given format. PHP, being derived from C, has the same function with some added features. But in Python, the function is totally excluded 🙁

Python developers believe that there should be two seperate procedures to print a formatted string – format a string and then print it. So python has a different mechanism of doing the task.

Lets see some language specific examples:

# include <stdio.h>
int main() { printf("%s is a string while %d is a number","maSnun",23); }

1 2	# include <stdio.h> int main() { printf("%s is a string while %d is a number","maSnun",23); }

PHP:

<?php printf("%s is a string while %d is a number","maSnun",23); ?>

1	<?php printf("%s is a string while %d is a number","maSnun",23); ?>

Python: (Python 3)

s = "%s is a string while %d is a number" % ("maSnun", 23)
print(s)

1 2	s = "%s is a string while %d is a number" % ("maSnun", 23) print(s)

Here, we format a string using the % (Modulo sign) or string formatting operator or the interpolation operator. If there was a single argument required for the formatting, we would simply pass it after the second modulo. Example:

s = “%s is a string ” % “maSnun”

But if we need to pass more than one argument to the formatting operator, we will have to pass a tuple of the arguments (like I have done in the first example). A tuple is an ordered collection which cannot be modified once it has been created. In other words, it’s rather like a read only array.

More About Tuples
You set up a tuple with round brackets (not
the square brackets you use to set up a list),
but you then access the individual members of
either with square brackets. That means that
you can use common code to process an ordered
collection, whether it’s a list or a tuple

demo = (1, 3, 6, 10, 15, 21, “lots”)

Python

Python: Encoding and Decoding Strings as Bytes

Post author By masnun
Post date May 2, 2009

It’s simple!

Python IDE Entries:

>>> s = "masnun"
>>> s
'masnun'
>>>s =  s.encode()
>>> s
b'masnun'
>>> s = s.decode()
>>> s
'masnun'

>>> s = "masnun"

>>> s

'masnun'

>>>s = s.encode()

>>> s

b'masnun'

>>> s = s.decode()

>>> s

'masnun'

It’s quite interesting. Last night, when I was using urlopen to access the TinyURL API, I found that the data was being returned as bytes. I had to decode it.

Python

Python Program To Generate TinyURLs

Post author By masnun
Post date May 1, 2009

In a previous post of mine, I have published a php class to generate short urls using the TinyURL API. Here is a simple Python program to generate tiny URLs directly from your desktop.

The File: (Python 3)

import sys;
from urllib.request import urlopen;
url = str(sys.argv[1]);
data = urlopen("http://tinyurl.com/api-create.php?url="+url);
print(data.readlines()[1].decode());

import sys;

from urllib.request import urlopen;

url = str(sys.argv[1]);

data = urlopen("http://tinyurl.com/api-create.php?url="+url);

print(data.readlines()[1].decode());

How To use?
Save the file as “tinyurl.py”.
You have to pass a target URL as the only argument to the program. The short url will be printed out on your screen.
Type the following command on your cmd or shell to execute the program.

tinyurl.py https://masnun.com

The short url will be printed out on the screen (shell or cmd).

If you don’t know or like the idea of copying text from the command line interface, simply redirect the output of the program to a text file:

tinyurl.py https://masnun.com > url.txt

The above code will fetch the short URL and put it into the file named “url.txt” 🙂 I use this method.

To Do: I am thinking of adding the functionality to create multiple short url from a single execution.

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