如何使用 f 字符串打印数学符号（使用乳胶），如 sigma？

Question

x = np.array([5,4,3])
y = np.array([1,2,3])
print(f"{sum(x*y)}, {sum(x**2)}, {sum(y**2)}")
#> 22, 50, 14

I want to print with the mathematical symbols displayed

But when I use f-string

print(f"$\sum{xy}$ = {sum(x*y)}, $\sum{x^2}$ = {sum(x**2)}, , $\sum{y^2}$ = {sum(y**2)}")

I get error: NameError: name 'xy' is not defined . Seems like f-strings are not able to recognize latex code.

What's the solution here?

Answer 1

I'm not sure I understood your question correctly, but the reason for the error is that Python recognizes the curly braces in your latex code and tries to format it as usual in the f-String, therefore not finding the xy variable, as it doesn't exist.

You have to escape the latex braces using double braces:

print(f"$\sum{{xy}}$ = {sum(x*y)}, and so on...”)

Answer 2

tl;dr: python can't print LaTex to terminal.

Usually, terminals are text only. That means that special LaTeX images cannot be displayed.

However, there are some ways that you can still view LaTeX (though not through terminal).

For example, you can call pdflatex through terminal (assuming you have it installed)

import os

latex = "Insert Latex Code here"
with open("latex.tex", "w") as file:
    file.write(latex)

os.system("pdflatex latex.tex")

Your LaTeX should be rendered as a pdf called latex.pdf