Python 字符串——巧取值和列表——巧取值 对比

Posted 2021-12-03 lyxcode

Python 字符串——巧取值和列表——巧取值 对比

1.字符串取值实例：

 

samp_string = "Whatever you are, be a good one."

for i in samp_string:
    print(i)
for i in range(0,len(samp_string)-2,2):
    print(samp_string[i]+samp_string[i+1])

print(‘A=‘,ord("A"))
print(‘65=‘,chr(65))

print(‘桃：‘,ord("桃"))
print(‘26690‘,chr(26690))


# # You can get a character by referencing an index
# print(samp_string[0])

print(samp_string[0])
# # Get the last character
print(samp_string[-2])
#
# # Get the string length
print("Length : ", len(samp_string))
#
# # Get a slice by saying where to start and end
# # The 4th index isn‘t returned
print(samp_string[0:4])
#
# # Get everything starting at an index
print(samp_string[8:])
# print()
#
print(samp_string)
print(samp_string[::])
print(samp_string[::2])
#
# # Reverse the string
print(samp_string[::-1])
# # Palindrome
print(‘I did, did I?‘[::-1])
print(‘No lemon, no melon‘[::-1])
#
# # Practical use
url = "http://pythonabc.org"
# Get the top level domain
print(url[-3:])
# Print the url without the http://
print(url[7:])
# Print the url without the http:// or the top level domain
print(url[7:-4])

 

2，列表取值取值实例

my_list=[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
#        0, 1, 2, 3, 4, 5, 6, 7, 8, 9
#       -10,-9,-8,-7,-6,-5,-4,-3,-2,-1

# 取其中一个值
print(my_list[0])
print(my_list[-10])
print(my_list[-1])

# 取其中几个值
print(my_list[0:5])
print(my_list[-10:-5])
print(my_list[-10:-5:2])

# 逆序输出
print(my_list[::-1])
print(my_list[-1:-10:-1]) # 注意逆序输出，开始点在结束点的后面
print(my_list[-1:-10:-2]) # 注意逆序输出，开始点在结束点的后面

strList=["string",520,21.0]
# 列表基本操作
print("列表长度：",len(strList))
print("列表输出",strList)
print("两个列表相加为一个列表：",my_list+strList)

# 判断一个元素是否为列表中的元素
print("string" in strList)
#  ************列表相关方法*************************8
# 找出特定元素的索引,字符串使用find方法找到，列表用index方法找到
print(strList.index(520))
for element in strList:
    print("{}:{}".format(strList.index(element),element))
# 特定元素的的个数   字符串和数组都是使用count方法计算特定子字符串和元素的个数
print("string 的个数：",strList.count(‘string‘))

# 添加元素
strList.append("final")
print("string 的更新后个数：",len(strList))