为什么利用read()方法不可以对文中单词进行计数?
```python
f = open('F:/word.txt', 'r', encoding="UTF-8")
content = f.read()
count = 0
for i in content:
if i == 'itheima':
count += 1
print(f'文中有{count}个itheima')
word.txt 的内容
itheima itcast python
itheima python itcast
beijing shanghai itheima
shenzhen guangzhou itheima
wuhan hangzhou itheima
zhengzhou bigdata itheima