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Python-using repetition structures nest loop to print patterns

Posted on Edited on Disqus:

Two repetition structures in python:

  • while loop
  • for loop

    Nest loop

    For loop has a nest loop function. clock is a good example.
    Nest loop can use to print some patterns.
    Some examples:
pattern 1
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6
rows = int(input('how many rows?'))
cols = int(input('how many columns?'))
for r in range(rows):
    for  c in range(cols):
        print('*',end='')
    print()

after input rows and clos value 6, runing code, it will show

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6
******
******
******
******
******
******
pattern 2
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7
*
**
***
****
*****
******
*******

code as following:

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base_size = 7
for r in range(base_size):
    for c in range(r+1):
        print('*',end='')
        print()
pattern 3: up side down triangle:
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*******
******
*****
****
***
**
*

code like this:

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rows =7
cols =7

for i in range(rows):
    #num_of_star = cols - i
    #print('*' * (cols - i))
    for j in range(cols - i):
        print('*', end='')
    print()
pattern 4:
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*
 *
  *
   *
    *
     *

code for this pattern is:

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num_step =6
for r in range(num_steps):
    for c in range(r):
        print(' ',end='')
    print('#')
pattern 5
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6
**
* *
*  *
*   *
*    *
*     *

code for this patter is:

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col = 6
raw = 6
for a in range(raw):
    print('#',end='', sep='')
    for b in range(a):
        print(' ', end='', sep='')
    print('#')