file = open('C:/Users/lo/Desktop/python/b.txt','w+')
file.write('A lot of people today are animal rights advocates\n Some of them are very\n Passionate and even quite radical about the issue\n But others argue that “wahuman rights” will always \n take priority. In fact, in many places even \n the most basic human rights are not adequately \n Protected So why animal rights? What do you \n think? And why?')
file = open("C:/Users/lo/Desktop/python/b.txt","r")
a=0
count = len(open("C:/Users/lo/Desktop/python/b.txt",'rU').readlines())
print("这个文件共有行数")
print(count)
b=0
fopen = open("C:/Users/lo/Desktop/python/b.txt", 'r')
lines = fopen.readlines()
for line in lines:
if line[0:1]=='P':
b=b+1
file.close()
print("首字母为P共有行数")
print(b)
因为你的换行符后面有空格，从第二行开始每行开头都是空格，line[0:1]=" "，所以不统计，把空格删掉或者匹配line[1:2]
把\n换成\r\n看看