Python金字塔实践问题生成不同的输出

Question

I was practicing pyramid patterns for a test in python. One question was about a pyramid pattern including 1s and 0s.

Output to generate:

1
10
101
1010
10101

Output that I got:

10
110
1110
11110
111110

My Efforts for this problem statement:

def pattern(n):
    for i in range(n):
        num = 1
        for j in range(i+1):
            print(num,end="")
        print(num-1)

What am i doing wrong?

Answer 1

You need to change num each time you go through the for j in range(i+1): loop, otherwise you'll just keep printing the same number like in your output. You could try changing num in each pass through the loop. The modulus operator % will be useful for switching back and forth between 0 and 1:

def pattern(n):
    for i in range(n):
        num = 1
        for j in range(i+1):
            print(num,end="")
            num = (num+1)%2

Answer 2

because output format is 1010101 , you should change num in loop, and you can use XOR ^ to switch between 0 and 1 :

    def pattern(n):
        for i in range(n):
            num = 1
            for j in range(i+1):
                print(num, end="")
                num ^= 1
            print()

test:

pattern(5)

output:

1
10
101
1010
10101