python新增练习（三）

f=open("poem.txt","r")
result = []
for line in f.readlines():
    line=line.strip()
    if len(line) != 0 and line[0] != "#":
        result.append(line)
result.sort()
for line in result:
    print(line)
f.close()

In [44]: '{:.2f}'.format(321.33345) Out[44]: '321.33' 2位小数

a = []
for i in range(8):
    a.append([])
    for j in range(8):
        a[i].append(0)
for i in range(8):
    a[i][0] = 1
    a[i][i]=1
for i in range(2,8):
    for j in range(1,i):
        a[i][j] = a[i-1][j-1]+a[i-1][j]
for i in range(8):
    for j in range(i+1):
        print("{:3d}".format(a[i][j]),end=" ")
    print()

def proc(strings):                     
    m = 0
    lst = []
    for i in range(len(strings)):
        if len(strings[i]) > m:       
            m = len(strings[i])
    for i in range(len(strings)):
        if len(strings[i]) == m:       
            lst.append(strings[i])
    return lst       


strings = ['cad' ,'VB', 'Python', 'MATLAB', 'hello', 'world']
result = proc(strings)
print("the longest words are:")
for item in result:
    print("{: >25}".format(item))

strings = {'cad', 'PE ', 'Window', 'FM', 'hello', 'world','flowers'}
n=0
for word in strings:
    if word.islower():
        n += 1
print(n) 

Python strip() 方法用于移除字符串头尾指定的字符（默认为空格）。

def proc(stu_list):
    d = {}
    for item in stu_list:
        r=item.split("_")
        a,b=r[0],r[1].strip()
        if a in d:
            d[a]+=[b]
        else:
            d[a]=[b]#值为列表
    lst = sorted(d.items(), key = lambda d:len(d[1]), reverse = True)
    return lst

f = open("signup.txt","r")        
stu_list = f.readlines()
result=proc(stu_list)
for item in result:
    print(item[0], '->', item[1])
f.close()

score={"lili":80,"xiaoqiang":75,"yunyun":89,"yuanyuan":90,"wanghao":85}
ls=list(score.items())
ls.sort(key=lambda x:x[1],reverse=True)
for i in range(3):
    print("{} {}".format(ls[i][0],ls[i][1]))