1.选择排序:
lst=[49,38,27,45,13]
for i in range(len(lst)):
for j in range(i+1,len(lst)):
if lst[i]>lst[j]:
lst[i],lst[j]=lst[j],lst[i]
print(lst)
附加冒泡排序:
lst=[49,38,27,45,13]
for i in range(len(lst)-1):
for j in range(len(lst)-i-1):
if lst[j]>lst[j+1]:
lst[j],lst[j+1]=lst[j+1],lst[j]
print(lst)
2.给一个日期,怎么判断是否是正常的日期
a='2920-12-02'
# a='20201001'
if len(a) == 10:
a = list(a)
for i in a:
if i == '-':
a.remove(i)
a = ''.join(a)
y=int(a[0:4])
m=int(a[4:6])
d=int(a[6:8])
if 0<m<13 and y>0:
if m in [1,3,5,7,8,10,12]:
if 0<d<=31:
print('是一个日期')
else:
print('no')
elif m in [4,6,9,11]:
if 0<d<=30:
print('是一个日期')
else:
print('no')
elif m==2:
if 0<d<=28:
print('是一个日期')
else:
print('no')
else:
print('不是一个日期')
3.给数字增加千位符
a.最简单的内置format函数:
format(1234567890,',')
b.正则表达式:
import re
def formatNum(num):
num=str(num)
pattern=r'(\d+)(\d{3})((,\d{3})*)'
while True:
num,count=re.subn(pattern,r'\1,\2\3',num)
if count==0:
break
return num
if __name__=='__main__':
print formatNum(1234455)
c.最笨的倒置后遍历过三位加逗号:
def formatNum(num):
num=str(num)
result=''
count=0
for i in num[::-1]:
count+=1
result+=i
if count%3==0:
result+=','
return result[::-1].strip(',')
if __name__=='__main__':
print formatNum(123445)