convert lower case to upper and upper to lower

21 visualizaciones (últimos 30 días)
Lauren Kinchla
Lauren Kinchla el 21 de Nov. de 2019
Respondida: Stephen23 el 23 de Mayo de 2022
I need help writing a code to flip the case of the characters so that lower case are converted to upper case and upper case characters are converted to lower case and any number values remains unchanged
  1 comentario
Star Strider
Star Strider el 21 de Nov. de 2019
There are MATLAB functions to do exactly that! This seems to be homework, so I will defer to you to explore the documentation.

Iniciar sesión para comentar.

Respuestas (2)

Stephen23
Stephen23 el 23 de Mayo de 2022
str = '123 Hello World!';
str = regexprep(str,'[A-Za-z]+','${char(mod($&-97,64)+65)}')
str = '123 hELLO wORLD!'

Jan
Jan el 21 de Nov. de 2019
Editada: Jan el 21 de Nov. de 2019
You can use the function isstrprop with the category 'lower' and 'upper' to identify the specific characters. Then use the commands upper and lower to change the case.
An alternative is to use a comparison:
str = 'aSd12Bqm'
low = (str >= 'a' & str <= 'z')
high = (str >= 'A' & str <= 'Z')
Now upper and lower can be useful again. But you can try it with calculations of the ASCII code also:
str = 'a'
str2 = str + ('A' - 'a')
char(str2)
A smart trick is to flip the 5th bit of the ASCII representation, if the character is a letter:
str = 'Aa'
char(bitxor(double(str), 32))
% 'aA'
% Coversion to DOUBLE is needed, because BITXOR cannot operate on CHARs
You have to use a mask to affect the letters only. See the creation of low and high above, which can be combined.
See:
doc char
doc isstrprop
doc lower

Categorías

Más información sobre Characters and Strings en Help Center y File Exchange.

Etiquetas

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by