Question

有人可以解释一般'格式说明符的工作原理吗？我很困惑左边对齐0填充如何工作。我不知道这是python中的错误，还是我根本不明白文档的内容。

在下面的输出中，我的混淆是在最后3个打印输出块中，特别是最右边的列。有人可以解释，参考文档格式规范，为什么它们会这样输出，请？

（这是Python 3.4.0 (v3.4.0:04f714765c13, Mar 16 2014, 19:25:23) [MSC v.1600 64 bit (AMD64)] on win32）

test.py：

t = [8123, 0.0, 1.0, 0.799999, 1.3243423487123]

for v in t:
    print(str.format("{0:9g} {0:9.6g} {0:09.6g} ", v))
print()

for v in t:
    print(str.format("{0:>9g} {0:>9.6g} {0:>09.6g} ", v))
print()

for v in t:
    print(str.format("{0:=9g} {0:=9.6g} {0:=09.6g} ", v))
print()



# What is going on with the right column here???
for v in t:
    print(str.format("{0:<9g} {0:<9.6g} {0:<09.6g} ", v))
print()

# What is going on with the right column here???
for v in t:
    print(str.format("{0:<9,g} {0:<9,.6g} {0:<09,.6g} ", v))
print()


# Preceding the width field by a zero ('0') character enables sign-aware zero-padding for numeric types.
# This is equivalent to a fill character of '0' with an alignment type of '='.
#
# Why doesn't this right column do the same thing as above?
for v in t:
    print(str.format("{0:0=9g} {0:0=9.6g} {0:0=09.6g} ", v))
print()

其输出为：

$ python3 test.py
     8123      8123 000008123 
        0         0 000000000 
        1         1 000000001 
 0.799999  0.799999 00.799999 
  1.32434   1.32434 001.32434 

     8123      8123 000008123 
        0         0 000000000 
        1         1 000000001 
 0.799999  0.799999 00.799999 
  1.32434   1.32434 001.32434 

     8123      8123 000008123 
        0         0 000000000 
        1         1 000000001 
 0.799999  0.799999 00.799999 
  1.32434   1.32434 001.32434 

8123      8123      812300000 
0         0         000000000 
1         1         100000000 
0.799999  0.799999  0.7999990 
1.32434   1.32434   1.3243400 

8,123     8,123     8,1230000 
0         0         000000000 
1         1         100000000 
0.799999  0.799999  0.7999990 
1.32434   1.32434   1.3243400 

000008123 000008123 000008123 
000000000 000000000 000000000 
000000001 000000001 000000001 
00.799999 00.799999 00.799999 
001.32434 001.32434 001.32434

Answer 1

使用Python的str.format解释这种行为＆＃34; general＆＃34;说明符，左对齐符号识别零填充。 {0：其中09.6克}

1 个答案: