In [ ]:
list(range(10,20,3))
Out[ ]:
[10, 13, 16, 19]
In [ ]:
for x in range(3):
    for y in range(4):
        print(x,y)

0 0
0 1
0 2
0 3
1 0
1 1
1 2
1 3
2 0
2 1
2 2
2 3
In [ ]:
for x in range(3):
    for y in range(x,4):
        print(x,y)

0 0
0 1
0 2
0 3
1 1
1 2
1 3
2 2
2 3
In [ ]:
p1 = [(5,3),(8,2),(9,3),(6,0)]

def list_to_dict(p):
    result = {}
    for x in p:
        if x[1] in result:
            result[x[1]] = result[x[1]] + x[0]
        else:
            result[x[1]] = x[0]
    return result

list_to_dict(p1)
Out[ ]:
{3: 14, 2: 8, 0: 6}
In [ ]:
def dict_to_list(d):
    result = []
    for e in d:
        result.append((d[e],e))
    return result

dict_to_list({3: 14, 2: 8, 0: 6})
Out[ ]:
[(14, 3), (8, 2), (6, 0)]
In [ ]:
def file_string_to_list(s):
    xs = s.split(",")
    result = []
    for y in xs:
        z = y.split(":")
        result.append((int(z[0]),int(z[1])))
    return result
In [ ]:
file_string_to_list("5:3,8:2,9:3,6:0")
Out[ ]:
[(5, 3), (8, 2), (9, 3), (6, 0)]
In [ ]:
with open("hello.txt","w") as f:
    f.write("Hello, how are you?\n")
    f.write("I am fine.\n")
f.close()