Test Your Skills: Python Thread

[zuzelvp]

[quote="[Gandalf] @ Thu Oct 02, 2008 8:00 am"]Roman, you couldn't do that because you're just using the join function and printing the result. The point is the re-implement it completely.

Here's my try:

Python:

def join(lst, sep):     return reduce(lambda x, y: x + sep + y, lst)

What I don't understand is, if we're not supposed to return anything or modifying any arguments, then what is the function supposed to do? Of course, there's probably some 'trick' that I'm missing completely.

!!![/quote]

join = lambda lst, sep: reduce(lambda x, y: x + sep + y, lst, '').replace(sep, '', 1)

[zuzelvp]

Hikaru79 @ Tue Nov 29, 2005 8:15 pm wrote:

Okay, my turn to give one This is my first try at this, so be gentle. I'll come up with more soon Here it is.

Add one line of code so that the following line executes properly (and gives the result that one would intuitively assume).

Python:

Dict(foo=5, bar=12, foobar=9)

I hope this isn't too easy, hard, pointless, etc

Anyone coming from languages like C# will need to learn this one

[DtY]

Hikaru79 @ Tue Nov 29, 2005 8:15 pm wrote:

Okay, my turn to give one This is my first try at this, so be gentle. I'll come up with more soon Here it is.

Add one line of code so that the following line executes properly (and gives the result that one would intuitively assume).

Python:

Dict(foo=5, bar=12, foobar=9)

I hope this isn't too easy, hard, pointless, etc

What do you mean "properly", I assume returns the dictionary that contains those?

Python:

Dict = dict # Or def Dict(**params): return params

Here's another, if anyone's interested;

In one line, write a function that will transpose a two dimensional list, that is, if the input were to look like this as a grid:

code:

A B C D E F G H I

The output looks like this:

code:

A D G B E H C F I

.
Some languages have a function that will do this, python doesn't, without using some syntax that may appear odd.
I'm pretty sure I learned how to do this from here, so at least one person should know right away.

[cavetroll]

DtY @ Sat May 22, 2010 2:15 pm wrote:

Hikaru79 @ Tue Nov 29, 2005 8:15 pm wrote:

Okay, my turn to give one This is my first try at this, so be gentle. I'll come up with more soon Here it is.

Add one line of code so that the following line executes properly (and gives the result that one would intuitively assume).

Python:

Dict(foo=5, bar=12, foobar=9)

I hope this isn't too easy, hard, pointless, etc

What do you mean "properly", I assume returns the dictionary that contains those?

Python:

Dict = dict # Or def Dict(**params): return params

Here's another, if anyone's interested;

In one line, write a function that will transpose a two dimensional list, that is, if the input were to look like this as a grid:

code:

A B C D E F G H I

The output looks like this:

code:

A D G B E H C F I

.
Some languages have a function that will do this, python doesn't, without using some syntax that may appear odd.
I'm pretty sure I learned how to do this from here, so at least one person should know right away.

I think for the transposing of a list, you can just do

Python:

zip(*lst)

Where lst is your initial two dimensional list. Although it will actually return a tuple of tuples, I assume that's what you were looking for?

[tedying]

Hikaru79 @ Tue Nov 29, 2005 8:15 pm wrote:

Okay, my turn to give one This is my first try at this, so be gentle. I'll come up with more soon Here it is.

Add one line of code so that the following line executes properly (and gives the result that one would intuitively assume).

Python:

Dict(foo=5, bar=12, foobar=9)

I hope this isn't too easy, hard, pointless, etc

def Dict(**x):
??return x

[tedying]

DtY @ Sat May 22, 2010 2:15 pm wrote:

Hikaru79 @ Tue Nov 29, 2005 8:15 pm wrote:

Okay, my turn to give one This is my first try at this, so be gentle. I'll come up with more soon Here it is.

Add one line of code so that the following line executes properly (and gives the result that one would intuitively assume).

Python:

Dict(foo=5, bar=12, foobar=9)

I hope this isn't too easy, hard, pointless, etc

What do you mean "properly", I assume returns the dictionary that contains those?

Python:

Dict = dict # Or def Dict(**params): return params

Here's another, if anyone's interested;

In one line, write a function that will transpose a two dimensional list, that is, if the input were to look like this as a grid:

code:

A B C D E F G H I

The output looks like this:

code:

A D G B E H C F I

.
Some languages have a function that will do this, python doesn't, without using some syntax that may appear odd.
I'm pretty sure I learned how to do this from here, so at least one person should know right away.

My python definitely has this function:

>>> a=((1,2,3),(4,5,6),(7,8,9))
>>> zip(*a)
[(1, 4, 7), (2, 5, 8), (3, 6, 9)]

[tedying]

wtd @ Tue Nov 29, 2005 8:43 pm wrote:

Python:

for line in file("foo.txt"): print line

Add one line of code to this such that it prints "Whoops! Empty file." if there's nothing in the file.

for line in open("/dev/null"):
  print(line)
else:
  print("null")