CODEWITHSUNDEEP
pythonpython-3.x
Artus
Artus

Reputation: 173

How to repeat a while loop a certain number of times

As seen over here, there are two ways to repeat something a number of times. But it does not seem to work for me, so I was wondering if anybody could help.

Basically, I want to repeat the following 3 times

 import random
 a = []
 w = 0

 while w<4:
     x = random.uniform(1,10)
     print(x)
     print(w)
     a.append(w+x)
     print(a)
     w=w+1

Based on what the link says, this is what I did,

 import random
 a = []
 w = 0
 r = 0


 while r < 3: 
      while w<4:
          x = random.uniform(1,10)
          print(x)
          print(w)
          a.append(w+x)
          print(a)
          w = w+1
      r += 1

But this doesn't seem to work. The while loop only repeats once instead of three times. Could anybody help me fix this problem?

Upvotes: 6

Views: 73148

Answers (3)

Roll
Roll

Reputation: 299

To repeat something for a certain number of times, you may:

  1. Use range or xrange

    for i in range(n):
    # do something here

  2. Use while

    i = 0
while i < n:
    # do something here
    i += 1

  3. If the loop variable i is irrelevant, you may use _ instead

    for _ in range(n):
    # do something here

_ = 0
while _ < n
    # do something here
    _ += 1

As for nested while loops, remember to always keep the structure:

i = 0
while i < n:

    j = 0
    while j < m:
        # do something in while loop for j
        j += 1

    # do something in while loop for i
    i += 1

Upvotes: 11

Tinsten
Tinsten

Reputation: 356

As stated by @R2RT, you need to reset w after each r loop. Try writing this: 

import random
 a = []
 w = 0
 r = 0


 while r < 3: 
      while w<4:
          x = random.uniform(1,10)
          print(x)
          print(w)
          a.append(w+x)
          print(a)
          w = w+1
      r += 1
      w = 0

Upvotes: 4

Max
Max

Reputation: 31

I dont see the

w=w+1

in your code, why you removed that? Add w=w+1 before r=r+1.

Good luck.

Upvotes: 3

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