实验4

with open('data1_1.txt', 'r', encoding = 'utf-8') as f:
    data=f.readlines()
n = 0
for line in data:
    if line.strip('\n') == '':
        continue
    n+=1
print(f'共{n}行')

with open('data1_1.txt', 'r', encoding = 'utf-8') as f:
    n = 0
    for line in f:
         if line.strip('\n') == '':
            continue
         n += 1
print(f'共{n}行')

with open('data1_2.txt', 'r', encoding = 'utf-8') as f:
    n = 0
    for line in f:
        if line.strip() == '':
            continue
        n += 1
print(f'共{n}行')

with open('data1_2.txt', 'r', encoding = 'utf-8') as f:
    n = 0
    for line in f:
        if line.isspace():
            continue
        n += 1
print(f'共{n}行')

with open('data2.txt', 'r', encoding = 'utf-8') as f:
    data = f.read().split('\n')
unique_line = []
for line in data:
    if data.count(line) == 1:
        unique_line.append(line)
print(f'共{ len(unique_line) }独特行')
for i in unique_line:
    print(i)

ls = [ ['城市', '大致人口'],
   ['南京', '850万'],
   ['纽约', '2300万'],
   ['东京', '3800万'],
   ['巴黎', '1000万'] ]
with open('data3.csv', 'w', encoding = 'utf-8') as f:
  for line in ls:
    data = ','.join(line) + '\n'
    f.write(data)
# 从data3.csv中读出数据，把逗号替换成\t, 分行打印输出到屏幕上
with open('data3.csv', 'r', encoding = 'utf-8') as f:
  data = f.read()
print(data.replace(',', '\t'), end = '')

 

>>> import datetime
>>> t = datetime.datetime.now()
>>> t.strftime('%Y%m%d')
'20210509'
>>> type( t.strftime('%Y%m%d') )
<class 'str'>

with open('data6_1.txt', 'r', encoding = 'utf-8') as f:
    x = []
    data = f.readlines()
    for i in data:
        x.append(i.strip().split())
f = lambda x:x[2]
x.sort(key=f,reverse=True)
 
with open('data6_2.txt','w',encoding='utf-8') as fn:
    for j in x:
        data1 = ' ' .join(j)
        data2 = ' '.join(j) + '\n'
        print(data1)
        fn.write(data2)

q = []
with open('data7.txt', 'r') as f:
    data = f.readlines()
    x = input('输入随机抽点人数：')
    import random
    i = 0
    while i<int(x):
        y = random.choice(data)
        i = i+1
        q.append(y)
        print(y.strip())
 
with open('lucky.txt','w') as fn:
    for j in q:
        k = ''.join(j)
        fn.write(k)