python mac地址大写还是小写_Python笔记：大小写转换

1. 将数据表中某一个字段全部转换成小写

# 将数据表中某一个字段全部转换成小写

# 加载数据源

import pandas as pd

df_lower = pd.read_excel("D:JupyterdataPython.xlsx",sheet_name = 1)

# 预览

df_lower

全部转换成小写

# 全部转换成小写

df_lower["goods"] = df_lower["goods"].str.lower()

df_lower

2. 字符串全部转换成小写字母

# 字符串全部转换成小写字母

str_lower = "BMW"

str_lower

# str_lower.lower()

str_lower.lower()

3. 将数据表中某一个字段全部转换成大写

# 将数据表中某一个字段全部转换成大写

import pandas as pd

df_upper = pd.read_excel("D:JupyterdataPython.xlsx",sheet_name = 1)

df_upper

df_upper["goods"] = df_upper["goods"].str.upper()

df_upper

4. 字符串全部转换成大写字母

# 字符串全部转换成大写字母

str_upper = "abcd"

str_upper

str_upper = str_upper.upper()

str_upper

5. 只把一句话的开头单词的首字母转换成大写

# 只把一句话的开头单词的首字母转换成大写

df_capitalize1 = "i have a lot of money"

df_capitalize1

df_capitalize2 = df_capitalize.capitalize()

df_capitalize2

或

df_capitalize3 = "who ARE YOU"

df_capitalize3

df_capitalize4 = df_capitalize3.capitalize()

df_capitalize4

6. 标题首字母大写

# 标题首字母大写

str_title = "wo yao zi xue wang"

str_title

str_title1 = str_title.title()

str_title1

7. 综合运用

x = input("请 输入字符：")

y = []

for n in x :

if "a"<= n <= "z":

y.append(n.upper())

elif"A" <= n <= "Z" :

y.append(n.lower())

else:

y.append(n)

print("".join(y))