sys.stdin的三种方式

1. for line in sys.stdin:

import sys

sys.stdout.write('根据两点坐标计算直线斜率k，截距b：
')
for line in sys.stdin:
    if line == '
': break
    
    x1, y1, x2, y2 = (float(x) for x in line.split())
    k = (y2 - y1) / (x2 - x1)
    b = y1 - k * x1
    sys.stdout.write('斜率:{}，截距:{}
'.format(k, b))

2. while True:
    　　line = sys.stdin.readline()

import sys

sys.stdout.write('根据两点坐标计算直线斜率k，截距b：
')
while True:
    line = sys.stdin.readline()
    if line == '
': break
    
    x1, y1, x2, y2 = (float(x) for x in line.split())
    k = (y2 - y1) / (x2 - x1)
    b = y1 - k * x1
    sys.stdout.write('斜率:{}，截距:{}
'.format(k, b))

3. while True:
    　　line = input()

print('根据两点坐标计算直线斜率k，截距b：')
while True:
    line = input()
    if line == '
': break
    
    x1, y1, x2, y2 = (float(x) for x in line.split())
    k = (y2 - y1) / (x2 - x1)
    b = y1 - k * x1
    print('斜率:{}，截距:{}'.format(k, b))