Python编程技巧与列表操作-优快云博客

本文链接：https://blog.youkuaiyun.com/rainy_killer/article/details/87886301

本文深入探讨了Python编程中的多种技巧，包括列表的元素交换、字符串操作、集合的高级功能、列表推导式和矩阵操作等。通过具体示例展示了如何使用Python处理常见数据结构，适用于初学者和进阶学习者。

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'''a=[1,2,3,4,5,6,7,8,9,]
for i in range(1,len(a),2):
    t=a[i]
    a[i]=a[i-1]
    a[i-1]=t
print(a)'''

a="1234567890abc"
c=0
t=1
for i in range(len(a)):
    print(a[i],end="")
    c+=1
    if c==t:
        print()
        c=0
        t+=1




'''a={1,2,3,4,5}
b={5,6,8,7,4}
c={2,3,4}
# a.add("python")       #添加一个
# print(a)
# a.update({3,4,5,7,9})      #添加集合
# print(a)
# a.pop()                 #随机删除，返回抛出的值，pop是抛出的意思
# print(a)
# a.remove("python")      #删除指定的值，没有会报错
# print(a)
# print(a.discard(9))     #删除指定的值，没有不会报错
# print(a)
# a.clear()
# print(a)

# new_a=a.union(b)
# print(new_a)
# new_a=a.intersection(b)
# print(new_a)
# new_a=a.difference(b)
# print(new_a)
# new_a=a.symmetric_difference(b)
# print(new_a)
#
# result=a.issuperset(c)
# print(result)
# result=c.issubset(a)
# print(result)
# result=a.isdisjoint(b)
# print(result)
# print(a-b)
# print(a|b)
# print(a&b)
# print(3 in a)
# print(3 not in a)
# for key,val in enumerate(c):
#     print(key,val)'''

'''a=[i for i in range(100)]
print(a)
a=[i for i in range(200,500) if i%5==0 or i%7==0 ]
print(a)'''

'''a=[[1,2,3],[4,5,6],[7,8,9]]
b=[a[i][2] for i in range(len(a))]
print(b)
b=[a[i][i] for i in range(len(a))]
print(b)
b=[a[i][len(a)-1-i] for i in range(len(a))]
print(b)'''

'''a=[[3*j+1+i for i in range(3)] for j in range(3)]
print(a)
a={1:20,3:40,5:60}
b={v:k for k,v in a.items()}
print(b)'''

'''a={"a":20,"b":30,"c":21,"A":2,"B":3}
b={k.lower():(a.get(k.lower(),0)+a.get(k.upper(),0)) for k in a}
print(b)

a=[2,3,45,6,87,4,32,32,45,5,65,6,76,4,3,5,5,4,3,43,45,5,]
set(a)
for i in set(a):
    print("%d出现了%d次"%(i,a.count(i)))'''

作业222