Characters of a string into a list

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Python Practice › Loop Programs › Program 48

Characters of a string into a list

EasyLoop Programs · 48 of 90

Write a Python program that adds every character of an input string to an empty list.

Input
sqatools007
Output
Enter text: sqatools007
['s', 'q', 'a', 't', 'o', 'o', 'l', 's', '0', '0', '7']

Approach

  1. Append each character in a loop.

Solution

Python
text = input("Enter text: ")chars = []for ch in text:    chars.append(ch)print(chars)
Outputtyped input: sqatools007
Enter text: sqatools007
['s', 'q', 'a', 't', 'o', 'o', 'l', 's', '0', '0', '7']
Tip

list(text) gives the same list in one call.

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Star pyramid

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Python Practice › Loop Programs › Program 44

Star pyramid

EasyLoop Programs · 44 of 90

Write a Python program to print a pyramid of stars with 5 rows (1, 3, 5, 7, 9 stars).

Output
    *
   ***
  *****
 *******
*********

Approach

  1. Row i has 2i - 1 stars and n - i leading spaces.

Solution

Python
n = 5for i in range(1, n + 1):    print(" " * (n - i) + "*" * (2 * i - 1))
Output
    *
   ***
  *****
 *******
*********

Line by line

Line 3

Fewer spaces and more stars on each row make the pyramid shape.

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Letter A pattern

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Python Practice › Loop Programs › Program 43

Letter A pattern

MediumLoop Programs · 43 of 90

Write a Python program to print the letter ‘A’ with stars.

Output
  * * * *   
*         * 
*         * 
* * * * * * 
*         * 
*         * 
*         *

Approach

  1. Row 0 is the rounded top, the middle row is the cross bar, and the other rows have stars on both sides.

Solution

Python
rows, cols = 7, 6for r in range(rows):    line = ""    for c in range(cols):        top = r == 0 and 0 < c < cols - 1        bar = r == rows // 2        sides = r > 0 and c in (0, cols - 1)        line += "* " if top or bar or sides else "  "    print(line)
Output
  * * * *   
*         * 
*         * 
* * * * * * 
*         * 
*         * 
*         *

Line by line

Line 5

The top row has stars only between the corners.

Line 6

The middle row (index 3) is the full cross bar.

Line 7

Every other row has stars at the two edges.

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Number diamond pattern

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Python Practice › Loop Programs › Program 42

Number diamond pattern

HardLoop Programs · 42 of 90

Write a Python program to print rows of numbers that grow from 1 to 5 numbers (1 to 15) and then shrink, counting back down (14 to 5).

Output
 1
 2  3
 4  5  6
 7  8  9 10
11 12 13 14 15
14 13 12 11
10  9  8
 7  6
 5

Approach

  1. Upper half: keep a counter that increases across rows of length 1 to 5.
  2. Lower half: continue from 14 counting down, rows of length 4 to 1.

Solution

Python
n = 5num = 1for row in range(1, n + 1):    print(" ".join(f"{num + i:2}" for i in range(row)))    num += rownum -= 2                     # last printed was 15, continue from 14for row in range(n - 1, 0, -1):    print(" ".join(f"{num - i:2}" for i in range(row)))    num -= row
Output
 1
 2  3
 4  5  6
 7  8  9 10
11 12 13 14 15
14 13 12 11
10  9  8
 7  6
 5

Line by line

Line 4

Each row prints row consecutive numbers starting at num.

Line 5

The next row starts after the numbers just printed.

Line 6

After the top half num is 16, so subtracting 2 gives 14.

Lines 7-9

The lower half counts down, row lengths 4, 3, 2, 1.

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Letter T pattern

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Python Practice › Loop Programs › Program 41

Letter T pattern

MediumLoop Programs · 41 of 90

Write a Python program to print the letter ‘T’ with stars: two full rows of 9 stars and a 3-star stem in the middle.

Output
* * * * * * * * * 
* * * * * * * * * 
      * * * 
      * * * 
      * * * 
      * * * 
      * * *

Approach

  1. Print the top bar twice, then the stem rows padded with spaces to centre them.

Solution

Python
width, stem, height = 9, 3, 5for _ in range(2):    print("* " * width)pad = (width - stem) // 2for _ in range(height):    print("  " * pad + "* " * stem)
Output
* * * * * * * * * 
* * * * * * * * * 
      * * * 
      * * * 
      * * * 
      * * * 
      * * *

Line by line

Line 3

"* " * 9 repeats the star-space pair 9 times.

Line 4

The stem starts 3 star-widths in, so it sits in the centre.

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Keep only the digits of the input

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Python Practice › Loop Programs › Program 47

Keep only the digits of the input

EasyLoop Programs · 47 of 90

Write a Python program that reads text and adds each digit to an empty list as a number.

Input
125python
Output
Enter text: 125python
[1, 2, 5]

Approach

  1. Loop over the characters and append the digits converted with int().

Solution

Python
text = input("Enter text: ")numbers = []for ch in text:    if ch.isdigit():        numbers.append(int(ch))print(numbers)
Outputtyped input: 125python
Enter text: 125python
[1, 2, 5]

Line by line

Line 4

isdigit() skips the letters.

Line 5

int(ch) stores numbers, not digit characters.

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Count odd numbers 1 to 100

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Python Practice › Loop Programs › Program 46

Count odd numbers 1 to 100

EasyLoop Programs · 46 of 90

Write a Python program to count the odd numbers from 1 to 100.

Output
50

Approach

  1. Increase a counter for each number with remainder 1.

Solution

Python
count = 0for n in range(1, 101):    if n % 2 != 0:        count += 1print(count)
Output
50

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Count even numbers 1 to 100

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Python Practice › Loop Programs › Program 45

Count even numbers 1 to 100

EasyLoop Programs · 45 of 90

Write a Python program to count the even numbers from 1 to 100.

Output
50

Approach

  1. Increase a counter for each number with remainder 0.

Solution

Python
count = 0for n in range(1, 101):    if n % 2 == 0:        count += 1print(count)
Output
50

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Multiplication table

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Python Practice › Loop Programs › Program 40

Multiplication table

EasyLoop Programs · 40 of 90

Write a Python program to print the multiplication table of a number.

Input
7
Output
7 x  1 =   7
7 x  2 =  14
7 x  3 =  21
7 x  4 =  28
7 x  5 =  35
7 x  6 =  42
7 x  7 =  49
7 x  8 =  56
7 x  9 =  63
7 x 10 =  70

Approach

  1. Loop from 1 to 10 and print each product.

Solution

Python
n = 7for i in range(1, 11):    print(f"{n} x {i:2} = {n * i:3}")
Output
7 x  1 =   7
7 x  2 =  14
7 x  3 =  21
7 x  4 =  28
7 x  5 =  35
7 x  6 =  42
7 x  7 =  49
7 x  8 =  56
7 x  9 =  63
7 x 10 =  70

Line by line

Line 3

The widths :2 and :3 right-align the columns.

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Fibonacci series of n terms

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Python Practice › Loop Programs › Program 39

Fibonacci series of n terms

EasyLoop Programs · 39 of 90

Write a Python program to print the first n terms of the Fibonacci series.

Input
n = 12
Output
0 1 1 2 3 5 8 13 21 34 55 89

Approach

  1. Loop n times, printing and advancing the pair.

Solution

Python
n = 12a, b = 0, 1for _ in range(n):    print(a, end=" ")    a, b = b, a + bprint()
Output
0 1 1 2 3 5 8 13 21 34 55 89

Line by line

Line 3

The loop runs exactly n times, one term per pass.

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