初识python： for循环之“两数之和”

#!/user/bin env python
# author:Simple-Sir
# time:20180913
# 给定一个整数数组和一个目标值，找出数组中和为目标值的两个数。

list1 = [1,2,3,4,5,6,7,8,9]
target = 10
num = 0
print(‘------------ 方法一 --------------------‘)
for id ,value in enumerate(list1):
    for id1 in range(id , len(list1)-1): # 起始值从id开始
        id1 += 1
        if list1[id] + list1[id1] == target:
            num += 1
            print(‘第{0}组:{1},{2}‘.format(num, list1[id], list1[id1]))
num = 0

print(‘------------ 方法二 --------------------‘)
for i in list1:
    for j in reversed(list1):
        if i == j:
            break
        if i+j == target:
            num += 1
            print(‘第{0}组:{1},{2}‘.format(num, i, j))
num = 0

print(‘------------ 方法三 --------------------‘)
for i in list1:
    for j in list1:
        if i+j == target :
            if i == j :
                exit()
            else:
                num += 1
                print(‘第{0}组:{1},{2}‘.format(num,i,j))