list declaration

[Kasrav]

hey guys it me again i got stuck in the middle of this program. The program starts with a list declaration of these numbers [1, 2, 4, 5, 6, 7, 8, 9, 10. 2, 53, 12] , i have to make sure the program outputs the following

1 The number of times 2 occurs in the list numbers
2 The position of the first occurrence of 2 in numbers.
3 The position of the next occurrence of 2 in numbers
4 The position of the last item in numbers
5 Sort the items of numbers.
6 The reversal of items in numbers.
7 Appending the value 99 to numbers.
8 Inserting -1 into numbers before position 0
9 Deletes and returns the last item of numbers.

and after each operation, i have to print out the list of numbers to show the
operation has been successful.

here is what i have got stuck on so far.

def declaration():
    numbers = ['1','2','4','5','6','7','8','9','10.2','53','12'];
    for i in range(1):
        print'number of times',2,'appears in the list:',numbers.count('2');
 

Sorry i tried to look for the posting guidelines to make sure that i post this programme right but i couldnt if someone can let me where i get it from thanks

[bvdet]

hey guys it me again i got stuck in the middle of this program. The program starts with a list declaration of these numbers [1, 2, 4, 5, 6, 7, 8, 9, 10. 2, 53, 12] , i have to make sure the program outputs the following

1 The number of times 2 occurs in the list numbers
2 The position of the first occurrence of 2 in numbers.
3 The position of the next occurrence of 2 in numbers
4 The position of the last item in numbers
5 Sort the items of numbers.
6 The reversal of items in numbers.
7 Appending the value 99 to numbers.
8 Inserting -1 into numbers before position 0
9 Deletes and returns the last item of numbers.

and after each operation, i have to print out the list of numbers to show the
operation has been successful.

here is what i have got stuck on so far.

def declaration():
numbers = ['1','2','4','5','6','7','8','9','10.2','53','12'];
for i in range(1):
print'number of times',2,'appears in the list:',numbers.count('2');

Sorry i tried to look for the posting guidelines to make sure that i post this programme right but i couldnt if someone can let me where i get it from thanks

I have posted this function a few times on the forum, and here it is again:

"""
Return an index list of all occurrances of 'item' in string/list 's'.
Optional start search position 'i'
"""
def indexList(s, item, i=0):
    i_list = []
    while True:
        try:
            i = s.index(item, i)
            i_list.append(i)
            i += 1
        except:
            return i_list

>>> numList = [1, 2, 4, 5, 6, 7, 8, 9, 10, 2, 53, 12]
>>> indexList(lst, 2)
[1, 9]
>>> 

Code tags should placed before and after your code. The beginning code tag is '[code=Python]'. The closing code tag is '[ / c o d e ]'. I put spaces in between the letters of the closing code tag so it would display.

[Smygis]

>>> lst = [1, 2, 4, 5, 6, 7, 8, 9, 10, 2, 53, 12]
>>> for i in dir(lst): print i
... 
# Cut away som stuff, All info you need down below
append
count
extend
index
insert
pop
remove
reverse
sort
>>> lst.count(2)
2
>>> lst.index(2)
1
# look at above post for this one
>>> len(lst)-1
11
>>> lst.sort()
>>> lst
[1, 2, 2, 4, 5, 6, 7, 8, 9, 10, 12, 53]
>>> lst.reverse()
>>> lst
[53, 12, 10, 9, 8, 7, 6, 5, 4, 2, 2, 1]
>>> lst.append(99)
>>> lst
[53, 12, 10, 9, 8, 7, 6, 5, 4, 2, 2, 1, 99]
>>> lst.insert(0,-1)
>>> lst
[-1, 53, 12, 10, 9, 8, 7, 6, 5, 4, 2, 2, 1, 99]
>>> lst.pop()
99
>>> lst
[-1, 53, 12, 10, 9, 8, 7, 6, 5, 4, 2, 2, 1]
 

[ghostdog74]

1 The number of times 2 occurs in the list numbers

you already know how to use count

2 The position of the first occurrence of 2 in numbers.
3 The position of the next occurrence of 2 in numbers

you can store them in a dictionary

d={}
a=[1, 2, 4, 5, 6, 7, 8, 9, 10, 2, 53, 12]
for num,item in enumerate(a):
    d.setdefault(item,[])
    d[item].append(num)
print d
 

output:

{1: [0], 2: [1, 9], 4: [2], 5: [3], 6: [4], 7: [5], 8: [6], 9: [7], 10: [8], 12: [11], 53: [10]}
 

the values will be the indexes of each number

4 The position of the last item in numbers

use len().

5 Sort the items of numbers.

sorted(a)
 

6 The reversal of items in numbers.

reversed(a) #note this is iterator

7 Appending the value 99 to numbers.

use the append() method

8 Inserting -1 into numbers before position 0

insert()

9 Deletes and returns the last item of numbers.

pop(), remove()

here is what i have got stuck on so far.

def declaration():
numbers = ['1','2','4','5','6','7','8','9','10.2','53','12'];
for i in range(1):
print'number of times',2,'appears in the list:',numbers.count('2');

and you should have already read the Python tutorial/references. these based stuffs are all covered in the Python documents.