How to write two variables in one line?

Question

I would like to write two variable in a file. I mean this is my code :

file.write("a = %g\n" %(params[0]))
file.write("b = %g\n" %(params[1]))

and what I want to write in my file is :

f(x) = ax + b

where a is params[0] and b is params[1] but I don't know how to do this ?

Thank you for your help !

you should look at the `format` string method – LB40 Apr 07 '17 at 18:57 — LB40, Apr 07 '17 at 18:57

blacksite · Answer 1 · 2017-04-07T19:25:19.927

1

If all you want to write to your file is f(x) = ax + b where a and b are params[0] and params[1], respectively, just do this:

file.write('f(x) = %gx + %g\n' % (params[0], params[1]))

'f(x) = %gx + %g' % (params[0], params[1]) is simply string formatting, where you're putting a and b in their correct spaces.

Edit: If you're using Python 3.6, you can use f-strings:

a, b = params[0], params[1]
file.write(f'f(x) = {a}x + {b}\n')

edited Apr 07 '17 at 19:25

answered Apr 07 '17 at 18:58

blacksite

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Does `file.write()` automatically add a newline? – Barmar Apr 07 '17 at 19:14
From reading the [docs](https://docs.python.org/3/library/io.html#io.TextIOWrapper), I didn't see anything indicating that a newline is automatically written. So you'd have to add the `'\n'` character at the end of the string. – blacksite Apr 07 '17 at 19:21
That's my point -- you forgot the newline. – Barmar Apr 07 '17 at 19:23
I thought I sensed a hint of a rhetorical question there :) – blacksite Apr 07 '17 at 19:25

score 0 · Answer 2 · answered Apr 07 '17 at 19:03

0

"f(x) = {a}x + {b}".format(a=params[0], b=params[1])

Is a clean solution

answered Apr 07 '17 at 19:03

PdevG

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score 0 · Answer 3 · answered Apr 07 '17 at 19:06

sorry I don't know Python, but I guess this

f = open('file', 'w')
x = 0;
a = 0;
b = 0;
result = a*x+b
a = str(a)
b = str(b)
x = str(x)
result = str(result)
f.write("f("+x+")="+result) #this is if you want result to be shown
print("f("+x+")="+result)

#or

f.write("f("+x+")="+a+""+x+"+"+b) #this is if you want actually show f(x)= ax+b
print("f("+x+")="+a+""+x+"+"+b)

again I don't know Python, but this is what I come up with by using : https://repl.it/HARP/1

I hope this helps

score 0 · Answer 4 · answered Apr 07 '17 at 19:09

You target is to achieve is to write the equation below to be written inside the file.

f(x) = ax + b where a is params[0] and b is params[1]

What you should do is

file.write('f(x) = %gx + %g' % (param[0], param[1]))

which will write

"f(x) = 2x + 3" # if params[0] and params[1] are 2 and 3 resp

What you are doing is

file.write("a = %g\n" %(params[0]))
file.write("b = %g\n" %(params[1]))

This will write in the file as:

a = 2
b = 3

if params[0] and params[1] are 2 and 3 respectively

How to write two variables in one line?

4 Answers4