Tensorflow暑期实践——作业1(python字数统计，Tensorflow计算1到n的和)

from collections import Counter
import re

f = open('罗密欧与朱丽叶(英文版)莎士比亚.txt',"r")
txt = f.read() 
txt = re.compile(r'\W+').split(txt.lower())

# 统计所有词出现的次数
splits = Counter(name for name in txt) 

# 输出出现次数排名前20的单词
top_n = sorted(splits.items(), key=lambda pair:pair[0], reverse=False)
top_n = sorted(top_n, key=lambda pair:pair[1], reverse=True)
for i in range 
print(top_n[:20])

[('and', 720), ('the', 681), ('i', 658), ('to', 577), ('a', 470), ('of', 401), ('my', 361), ('that', 355), ('is', 349), ('in', 320), ('you', 295), ('s', 293), ('thou', 278), ('me', 265), ('not', 260), ('with', 255), ('d', 236), ('it', 228), ('this', 226), ('for', 225)]

# 输出romeo和juliet出现的次数
print("罗密欧出现了: ",splits["romeo"]," 次")
print("朱丽叶出现了: ",splits["juliet"]," 次")

罗密欧出现了:  156  次
朱丽叶出现了:  66  次

1.计算1+2+...+10

import tensorflow as tf
import os
os.environ["CUDA_VISIBLE_DEVICES"] = "-1" 

value = tf.Variable(0,name="value")
sum0 = tf.Variable(0,name="sum")
one = tf.constant(1)
add0 = tf.add(sum0,value) #sum加上这个数
update_value_sum = tf.assign(sum0,add0) #将sum赋值
new_value = tf.add(value,one) #value值+1
update_value = tf.assign(value,new_value) #将value赋值


init = tf.global_variables_initializer()

with tf.Session() as sess:
    sess.run(init)
    for _ in range(10):
        sess.run(update_value) 
        sess.run(update_value_sum)
    print("1+2+...+10 =",sess.run(sum0))

1+2+...+10 = 55

2.计算1+2+...+n

(1)对输入的n使用占位符

import tensorflow as tf
import os
os.environ["CUDA_VISIBLE_DEVICES"] = "-1"
import numpy as np

a = int(input("请输入一个整数："))

value = tf.Variable(0,name="value")
sum0 = tf.Variable(0,name="sum")
one = tf.constant(1)

add0 = tf.add(sum0,value)
update_value_sum = tf.assign(sum0,add0)
new_value = tf.add(value,one) 
update_value = tf.assign(value,new_value) 


n = tf.placeholder(tf.int32)
toInt = tf.add(0,n)

init = tf.global_variables_initializer()

with tf.Session() as sess:
    sess.run(init)
    for _ in range(sess.run(toInt,feed_dict={n:a})):
        sess.run(update_value) 
        sess.run(update_value_sum)
    print("1+2+...+ %d = %d" % (a,sess.run(sum0)))

请输入一个整数：100
1+2+...+ 100 = 5050

(2)对中间变量使用占位符

import tensorflow as tf

n = int(input("请输入一个整数："))

value = tf.Variable(0,name="value")
one = tf.constant(1)
temp = tf.placeholder(tf.int32, name="temp")
result = tf.Variable(0,name="value")

new_value = tf.add(value,one) 
update_value = tf.assign(value,new_value) 
new_result = tf.add(result,temp)
update_result = tf.assign(result,new_result)

init = tf.global_variables_initializer()

with tf.Session() as sess:
    sess.run(init)
    for _ in range(n):
        sum0 = sess.run(update_result, feed_dict={temp:sess.run(update_value)})
print("1+2+...+ %d = %d" % (n,sum0))

请输入一个整数：101
1+2+...+ 101 = 5151

3.模拟矩阵运算 [[1.0, 2.0], [3.0, 4.0]] + [[5, 6], [7, 8]] * 9 – 10E

import tensorflow as tf

a = tf.Variable([[1.0, 2.0], [3.0, 4.0]], dtype=tf.float32)
b = tf.Variable([[5.0, 6.0], [7.0, 8.0]], dtype=tf.float32)
e = tf.eye(2) # 二阶单位阵
result = a+b*9-10*e

with tf.Session() as sess:
    sess.run(tf.global_variables_initializer())
    print("最终结果是:\n",sess.run(result))

最终结果是:
 [[36. 56.]
 [66. 66.]]