在小数点分隔符之前也在python中格式化浮点数

Question

I am formatting floats as follows:

logFile.write("Loadcase: %6i %2i %4i %2.2f %2.2f %4f + %4f -> " %(i, freq, amp, cutoff, end_time, penalty_inc, stab_inc))

and the result is like:

Loadcase:   5001  1   50 19.00 20.00 0.000000 + 0.000000 -> 0.495386 (ok)
Loadcase:   5002  2   50 9.50 10.00 0.000000 + 0.000000 -> 0.255045 (ok)
Loadcase:   5003  3   50 6.33 6.67 0.000000 + 0.000000 -> 0.151464 (ok)
Loadcase:   5005  5   50 3.80 4.00 0.000000 + 0.000000 -> 0.116979 (ok)
Loadcase:   5010 10   50 1.90 2.00 0.000000 + 0.000000 -> 0.081181 (ok)

I simply want the floats to be right aligned and some spaces inserted where necessary. I really basically want the table to be nicely aligned. My guess of writing %2.2f seems to be ignored.

I cannot use numpy for technical reasons.

Answer 1

You're misunderstanding what %2.2f means. It means "give the float 2 columns total, and display 2 positions after the radix point". Perhaps you want %5.2f instead.

Answer 2

The syntax is

% fieldwidth . precision conversiontype

So in you want to leave some space, and show 2 decimals, try

%8.2f

See the Python documentation for a full overview.

Answer 3

The format string "%4.2f" says: format with 2 digits after radix point and use at least 4 characters for the full string . So

 "%4.2f" % 1.1   -->  " 1.1"
 "%4.2f" % 11.1  -->  "11.1"
 "%4.2f" % 111.1 -->  "111.1"

In your case you have the set the 4 above high enough.

Answer 4

I am using pycharm professional

this is my code for converting fahrenheit from Celsius

function to convert Celsius to fahrenheit

def temperature():
print("Celsius_Degree       Fahrenheit_Degree")
print("==============       =================")
for Celsius in range(0, 101, 1):
    fahrenheit = (9/5) * Celsius + 32
    print("{:>5.1f} C               {:>5.1f} F".format(Celsius, fahrenheit))

temperature()

so when I change :>5.1f to %5.1f why am I getting KeyError: '%5'

I have added the 2 output screenshot of the error as well a screenshot of no error, please explain; I am getting confused which one I am supposed to use %5.1f or :>5.1f Error with writing %5.1f no error with writing :>5.1f