CODEWITHSUNDEEP
pythonlistfor-loopwhile-loopvariable-assignment
therion
therion

Reputation: 445

Assignment of Different Values to Single Variable each Iteration

There is a list s and two variables m and n:

s = [3, 'abc', '123', 'def', '456', 'ghi', '789']

s[0] is type int. It represents the number of times an iteration should occur to assign the following values to m and n. Ex: This list of s should be iterated 3 times as denoted by s[0]. Each iteration should assign a new value from s to m and n.

First iteration, m and n should be assigned

m = 'abc'
n = '123'

Second iteration, 

m = 'def' 
n = '123'`

third iteration, 

m = 'ghi' 
n = '789'

What I have tried so far -

s = [3, 'abc', '123', 'def', '456', 'ghi', '789']

count = 0
i = 0
j = 2
while count < s[0]:
     m = s[i+1]
     n = s[j+1]
     print(m)
     print(n)
     count += 1
     i += 1
     j += 1

My ouput is 

abc
def
123
456
def
ghi

instead of 

abc 
123
def
456
ghi
789

Please help me to build the needed logic to get through this.

Upvotes: 0

Views: 366

Answers (4)

ansev
ansev

Reputation: 30920

You could do this:

s = [3, 'abc', '123', 'def', '456', 'ghi', '789']
i = 1
count=1
while  count<=s[0]:
      m = s[i]
      n = s[i+1]
      print(m)
      print(n)
      i += 2
      count+=1

the indices i, j must be incremented two by two, on the other hand, only one of them is needed, since the value of j at all times would be i + 1.

Upvotes: 1

Abdullah Akhtar
Abdullah Akhtar

Reputation: 558

Its convenient when you make it work where one variable is == 0. Then to assign m and n you can follow and understand example below:

count = 0
for itervar in [3, 41, 12, 9, 74, 15]:
    count = count + 1
print 'Count: ', count

then

total = 0
for itervar in [3, 41, 12, 9, 74, 15]:
    total = total + itervar
print 'Total: ', total

You can increase the number of iterations you want.

Upvotes: 0

Piotr Kamoda
Piotr Kamoda

Reputation: 1006

I think that we can simplify this by saying that in our loop the loop counter is equal to s[0]*2. This way we can define loop step to be 2. But this means that s[0] has to be smaller or equal to (len(s) -1)/2

>>> s = [3, 'abc', '123', 'def', '456', 'ghi', '789']
>>> for i in range(1, s[0]*2, 2):
    print(s[i])
    print(s[i+1])


abc
123
def
456
ghi
789

Parameters to this range are:

  • First index = 1
  • Max index = 6
  • Increment each step = 2

So first loop we get i = 1 and we print indexes 1 and 2, then the index becomes 3 and we print 3 and 4, and so on.

Upvotes: 1

user2390182
user2390182

Reputation: 73460

You can just use an iterator and you won't have to manage indexes at all:

it = iter(s)
for _ in range(next(it)):
    m, n = next(it), next(it)
    print(m)
    print(n)

Or using index access:

i, j = 1, 2
for _ in range(s[0]):
    m, n = s[i], s[j]
    print(m)
    print(n)
    i, j = i+2, j+2

Upvotes: 4

Related Questions