Question

我有4个字典，某些字段在所有4个字典中都不存在。我收到此错误

ValueError：dict包含不在字段名称中的字段：'from'，'Command'

阅读一些文档后，我发现DictWriter的 extrasaction ='ignore'参数，但在CSV文件中却保留了一些字段。我需要CSV文件中的所有字段，即使某些字典中的字段为空。据我了解，它只是打印公共字段。

词典是：

{'Command'：'DELETE'，'table'：'abc'，'from'：'abc'，'where_expr'：'c = book'}

{'Command'：'SELECT'，'columns'：'a b'，'table'：'tab1'，'from'：'tab1'}

{'Command'：'INSERT'，'table'：'xyz'，'into'：'xyz'，'columns'：'铅笔笔'，'值'：'200 20'}

{'Command'：'UPDATE'，'table'：'Student'，'columns'：'NAME'，'values'：'PRATIK'，'where_expr'：'a = 100'}

由于错误，我包括了多余的行为。

with open('del.csv', 'w') as f:  
    write = csv.DictWriter(f, dict4.keys(),extrasaction='ignore') 
    write.writeheader()
    write.writerow(dict5)
    write.writerow(dict6)
    write.writerow(dict7)
    write.writerow(dict8)

输出看起来像：（我使用逗号分隔字段。空白表示空白字段（它们没有值））

表|列|值| where_expr

abc，，，c = book

tab1，a b，，

xyz，铅笔笔，200 20

学生，姓名，PRATIK，a = 100

已编辑：所需的输出是：（空格表示空白字段），我希望可以发布CSV文件。

Command | Table | Columns | From | Where_expr | Into | Values

DELETE，abc，，abc，c = book，，，

SELECT，tab1，a b，tab1，，，，

INSERT，xyz，铅笔，``，xyz，200 20

UPDATE，student，name，a = 100，PRATIK

Answer 1

您可以使用pandas数据框将所有词典加载到列表中，并从该数据框制作csv文件。试试这个：

jekyll serve --port

输出（CSV文件内容）：

   Source: /home/a__/repos/Bxgxaxdx.github.io
       Destination: /home/a__/repos/Bxgxaxdx.github.io/_site
 Incremental build: disabled. Enable with --incremental
      Generating... 
                    done in 0.029 seconds.
Traceback (most recent call last):
    32: from /usr/bin/jekyll:11:in `<main>'
    31: from /usr/lib/ruby/vendor_ruby/mercenary.rb:19:in `program'
    30: from /usr/lib/ruby/vendor_ruby/mercenary/program.rb:42:in `go'
    29: from /usr/lib/ruby/vendor_ruby/mercenary/command.rb:220:in `execute'
    28: from /usr/lib/ruby/vendor_ruby/mercenary/command.rb:220:in `each'
    27: from /usr/lib/ruby/vendor_ruby/mercenary/command.rb:220:in `block in execute'
    26: from /usr/lib/ruby/vendor_ruby/jekyll/commands/serve.rb:34:in `block (2 levels) in init_with_program'
    25: from /usr/lib/ruby/vendor_ruby/jekyll/commands/build.rb:39:in `process'
    24: from /usr/lib/ruby/vendor_ruby/jekyll/commands/build.rb:72:in `watch'
    23: from /usr/lib/ruby/vendor_ruby/jekyll/watcher.rb:10:in `watch'
    22: from /usr/lib/ruby/vendor_ruby/listen/listener.rb:91:in `start'
    21: from /usr/lib/ruby/vendor_ruby/listen/fsm.rb:57:in `transition'
    20: from /usr/lib/ruby/vendor_ruby/listen/fsm.rb:91:in `transition_with_callbacks!'
    19: from /usr/lib/ruby/vendor_ruby/listen/fsm.rb:121:in `call'
    18: from /usr/lib/ruby/vendor_ruby/listen/fsm.rb:121:in `instance_eval'
    17: from /usr/lib/ruby/vendor_ruby/listen/listener.rb:68:in `block in <class:Listener>'
    16: from /usr/lib/ruby/2.6.0/forwardable.rb:230:in `start'
    15: from /usr/lib/ruby/vendor_ruby/listen/adapter/base.rb:63:in `start'
    14: from /usr/lib/ruby/vendor_ruby/listen/adapter/base.rb:40:in `configure'
    13: from /usr/lib/ruby/vendor_ruby/listen/adapter/base.rb:40:in `each'
    12: from /usr/lib/ruby/vendor_ruby/listen/adapter/base.rb:45:in `block in configure'
    11: from /usr/lib/ruby/vendor_ruby/listen/adapter/linux.rb:30:in `_configure'
    10: from /usr/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require'
     9: from /usr/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require'
     8: from /usr/lib/ruby/vendor_ruby/rb-inotify.rb:1:in `<top (required)>'
     7: from /usr/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require'
     6: from /usr/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require'
     5: from /usr/lib/ruby/vendor_ruby/rb-inotify/native.rb:1:in `<top (required)>'
     4: from /usr/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require'
     3: from /usr/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require'
     2: from /usr/lib/ruby/vendor_ruby/ffi.rb:4:in `<top (required)>'
     1: from /usr/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require'
/usr/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require': **cannot load such file -- 2.6/ffi_c (LoadError)**
    33: from /usr/bin/jekyll:11:in `<main>'
    32: from /usr/lib/ruby/vendor_ruby/mercenary.rb:19:in `program'
    31: from /usr/lib/ruby/vendor_ruby/mercenary/program.rb:42:in `go'
    30: from /usr/lib/ruby/vendor_ruby/mercenary/command.rb:220:in `execute'
    29: from /usr/lib/ruby/vendor_ruby/mercenary/command.rb:220:in `each'
    28: from /usr/lib/ruby/vendor_ruby/mercenary/command.rb:220:in `block in execute'
    27: from /usr/lib/ruby/vendor_ruby/jekyll/commands/serve.rb:34:in `block (2 levels) in init_with_program'
    26: from /usr/lib/ruby/vendor_ruby/jekyll/commands/build.rb:39:in `process'
    25: from /usr/lib/ruby/vendor_ruby/jekyll/commands/build.rb:72:in `watch'
    24: from /usr/lib/ruby/vendor_ruby/jekyll/watcher.rb:10:in `watch'
    23: from /usr/lib/ruby/vendor_ruby/listen/listener.rb:91:in `start'
    22: from /usr/lib/ruby/vendor_ruby/listen/fsm.rb:57:in `transition'
    21: from /usr/lib/ruby/vendor_ruby/listen/fsm.rb:91:in `transition_with_callbacks!'
    20: from /usr/lib/ruby/vendor_ruby/listen/fsm.rb:121:in `call'
    19: from /usr/lib/ruby/vendor_ruby/listen/fsm.rb:121:in `instance_eval'
    18: from /usr/lib/ruby/vendor_ruby/listen/listener.rb:68:in `block in <class:Listener>'
    17: from /usr/lib/ruby/2.6.0/forwardable.rb:230:in `start'
    16: from /usr/lib/ruby/vendor_ruby/listen/adapter/base.rb:63:in `start'
    15: from /usr/lib/ruby/vendor_ruby/listen/adapter/base.rb:40:in `configure'
    14: from /usr/lib/ruby/vendor_ruby/listen/adapter/base.rb:40:in `each'
    13: from /usr/lib/ruby/vendor_ruby/listen/adapter/base.rb:45:in `block in configure'
    12: from /usr/lib/ruby/vendor_ruby/listen/adapter/linux.rb:30:in `_configure'
    11: from /usr/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require'
    10: from /usr/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require'
     9: from /usr/lib/ruby/vendor_ruby/rb-inotify.rb:1:in `<top (required)>'
     8: from /usr/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require'
     7: from /usr/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require'
     6: from /usr/lib/ruby/vendor_ruby/rb-inotify/native.rb:1:in `<top (required)>'
     5: from /usr/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require'
     4: from /usr/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require'
     3: from /usr/lib/ruby/vendor_ruby/ffi.rb:3:in `<top (required)>'
     2: from /usr/lib/ruby/vendor_ruby/ffi.rb:6:in `rescue in <top (required)>'
     1: from /usr/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require'
/usr/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require': **cannot load such file -- ffi_c (LoadError)**

Answer 2

使用set.union操作（对于动态列数的情况）：

import csv

dict5 = {'Command': 'DELETE', 'table': 'abc', 'from': 'abc', 'where_expr': 'c = book'}
dict6 = {'Command': 'SELECT', 'columns': 'a b', 'table': 'tab1', 'from': 'tab1'}
dict7 = {'Command': 'INSERT', 'table': 'xyz', 'into': 'xyz', 'columns': 'pencil pens', 'values': '200 20'}
dict8 = {'Command': 'UPDATE', 'table': 'Student', 'columns': 'NAME', 'values': 'PRATIK', 'where_expr': 'a = 100'}

with open('names.csv', 'w', newline='') as csvfile:
    # `initial_fieldnames` are your dict4 keys
    initial_fieldnames = ["table", "columns", "values", "where_expr"]
    fieldnames = sorted(set(initial_fieldnames).union(*[dict5, dict6, dict7, dict8]))
    writer = csv.DictWriter(csvfile, fieldnames=fieldnames, extrasaction='ignore')

    writer.writeheader()
    writer.writerows([dict5, dict6, dict7, dict8])

names.csv内容：

Command,columns,from,into,table,values,where_expr
DELETE,,abc,,abc,,c = book
SELECT,a b,tab1,,tab1,,
INSERT,pencil pens,,xyz,xyz,200 20,
UPDATE,NAME,,,Student,PRATIK,a = 100

我需要打印具有不同字段的不同字典，ValueError：dict包含不在字段名称中的字段：

2 个答案: