Floating numbers and str

[Tuvas]

I would like to limit a floating variable to 4 signifigant digits, when
running thorugh a str command. Ei,
x=.13241414515
y=str(x)+" something here"

But somehow limiting that to 4 sign. digits. I know that if you use the
print statement, you can do something like %.4d, but how can I do this
with converting the number to a string? Thanks!

[Jeffrey Schwab]

Tuvas wrote:

I would like to limit a floating variable to 4 signifigant digits, when
running thorugh a str command. Ei,
x=.13241414515
y=str(x)+" something here"

But somehow limiting that to 4 sign. digits. I know that if you use the
print statement, you can do something like %.4d, but how can I do this
with converting the number to a string? Thanks!

%d for a floating-point type? Is that right?

Anyway, ITYW:

"%.4g" % x

E.g:

x=.13241414515
y="%.4g something here" % x
print y 0.1324 something here

[Jeremy Moles]

I think you answered your own question. :)

x = 0.12345678
y = "%.4f something here" % x

On Wed, 2005-11-09 at 11:52 -0800, Tuvas wrote:

I would like to limit a floating variable to 4 signifigant digits, when
running thorugh a str command. Ei,
x=.13241414515
y=str(x)+" something here"

But somehow limiting that to 4 sign. digits. I know that if you use the
print statement, you can do something like %.4d, but how can I do this
with converting the number to a string? Thanks!

[Tuvas]

Yep, I was thinking in C, not python. Thanks for the help!

[Grant Edwards]

On 2005-11-09, Tuvas <tu*****@gmail.com> wrote:

I would like to limit a floating variable to 4 signifigant digits, when
running thorugh a str command.
Sorry, that's not possible.
x=.13241414515
y=str(x)+" something here"

But somehow limiting that to 4 sign. digits. I know that if
you use the print statement, you can do something like %.4d,
but how can I do this with converting the number to a string?

I don't understand what you mean about the print statement.

If using str() isn't really a requirement, you can use the
string formatting operator "%" like this:

x=.13241414515
y = "%0.4g" % x
y

'0.1324'

--
Grant Edwards grante Yow! A GRAM?? A BRAM... A
at GROOM... A BROOM... Oh,
visi.com Yeh!! Wash the ROOM!!

[Tuvas]

Wait, one more question. If the number is something like:

1.32042

It is like
"1.32 stuff"

I would like it's size to remain constant. Any way around this?

[Fredrik Lundh]

"Tuvas" <tu*****@gmail.com> wrote:

I would like to limit a floating variable to 4 signifigant digits, when
running thorugh a str command. Ei,

x=.13241414515
y=str(x)+" something here"

But somehow limiting that to 4 sign. digits. I know that if you use the
print statement, you can do something like %.4d, but how can I do this
with converting the number to a string? Thanks!

you mean "%.4g" ? the % operator is a string operator, and can be used
outside print:

text = "%.4g" % value

for more details, here's the first google hit for "python string formatting":

http://docs.python.org/lib/typesseq-strings.html

but that doesn't make too much sense if you don't know how things work
in C, which is explained here:

http://www.cplusplus.com/ref/cstdio/printf.html

here are some examples:

x=.13241414515
x 0.13241414515 "%.4f" % x '0.1324' "%.4g" % x '0.1324'
x=5.13241414515
"%.4f" % x '5.1324' "%.4g" % x

'5.132'

</F>

[Grant Edwards]

On 2005-11-09, Tuvas <tu*****@gmail.com> wrote:

Wait, one more question. If the number is something like:

1.32042

It is like
"1.32 stuff"

I would like it's size to remain constant. Any way around this?

http://www.python.org/doc/current/li...s.html#l2h-211

--
Grant Edwards grante Yow! WHO sees a BEACH
at BUNNY sobbing on a SHAG
visi.com RUG?!

[Dan Bishop]

Grant Edwards wrote:

On 2005-11-09, Tuvas <tu*****@gmail.com> wrote:

I would like to limit a floating variable to 4 signifigant digits, when
running thorugh a str command.

Sorry, that's not possible.

Technically, it is.

class Float4(float): .... def __str__(self):
.... return '%.4g' % self
.... x = Float4(1.23456789)
str(x)

'1.235'

But, of course, I'd recommend just using '%.4g'%x directly.

[Grant Edwards]

On 2005-11-10, Dan Bishop <da*****@yahoo.com> wrote:

Grant Edwards wrote:

On 2005-11-09, Tuvas <tu*****@gmail.com> wrote:

> I would like to limit a floating variable to 4 signifigant digits, when
> running thorugh a str command.

Sorry, that's not possible.

Technically, it is.

Ah well, I assumed that by "floating variable" he meant the
built-in "float" type.

--
Grant Edwards grante Yow! I always wanted a
at NOSE JOB!!
visi.com

[Jeffrey Schwab]

Tuvas wrote:

Wait, one more question. If the number is something like:

1.32042

It is like
"1.32 stuff"

I would like it's size to remain constant. Any way around this?

s/%g/%f

print "%.4f stuff" % 1.3241414515 1.3241 stuff print "%.4f stuff" % 1.32042 1.3204 stuff

[Christian Stapfer]

"Tuvas" <tu*****@gmail.com> wrote in message
news:11*********************@g44g2000cwa.googlegro ups.com...

I would like to limit a floating variable to 4 signifigant digits, when
running thorugh a str command. Ei,
x=.13241414515
y=str(x)+" something here"

But somehow limiting that to 4 sign. digits. I know that if you use the
print statement, you can do something like %.4d, but how can I do this
with converting the number to a string? Thanks!

from scipy import round

print round(0.13241414515,4)

Regards,
Christian