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Replacing Pandas or Numpy Nan with a None to use with MysqlDB
...s:
df1 = df.where(pd.notnull(df), None)
Note: this changes the dtype of all columns to object.
Example:
In [1]: df = pd.DataFrame([1, np.nan])
In [2]: df
Out[2]:
0
0 1
1 NaN
In [3]: df1 = df.where(pd.notnull(df), None)
In [4]: df1
Out[4]:
0
0 1
1 None
Note: what you ca...
Identifying and removing null characters in UNIX
...l with I/O redirection (<, >, …) anywhere in the command line, actually.
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@RequestBody and @ResponseBody annotations in Spring
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There is a whole Section in the docs called 16.3.3.4 Mapping the request body with the @RequestBody annotation. And one called 16.3.3.5 Mapping the response body with the @ResponseBody annotation. I suggest you consult those sections. Also relevant: @RequestBody ...
Implementation difference between Aggregation and Composition in Java
...e) and aggregation as a weak association (a Car without an Engine makes totally sense, it doesn't even need one in its constructor). Which one to use? Depends on the context.
– Federico Pugnali
Oct 26 '12 at 19:31
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PDO's query vs execute
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query runs a standard SQL statement and requires you to properly escape all data to avoid SQL Injections and other issues.
execute runs a prepared statement which allows you to bind parameters to avoid the need to escape or quote the parameters. execute will also perform better if you are repeat...
Linux日志管理Rsyslog入门 - C/C++ - 清泛网 - 专注IT技能提升
...g，其配置大致如下所示：
shell> cat /etc/syslog.conf
# Log all kernel messages to the console.
# Logging much else clutters up the screen.
# kern.* /dev/console
# Log anything (except mail) of level info or higher.
# Don't log private authentication messages!
*.info;mail.none;...
Linux日志管理Rsyslog入门 - C/C++ - 清泛网 - 专注IT技能提升
...g，其配置大致如下所示：
shell> cat /etc/syslog.conf
# Log all kernel messages to the console.
# Logging much else clutters up the screen.
# kern.* /dev/console
# Log anything (except mail) of level info or higher.
# Don't log private authentication messages!
*.info;mail.none;...
Linux日志管理Rsyslog入门 - C/C++ - 清泛网 - 专注IT技能提升
...g，其配置大致如下所示：
shell> cat /etc/syslog.conf
# Log all kernel messages to the console.
# Logging much else clutters up the screen.
# kern.* /dev/console
# Log anything (except mail) of level info or higher.
# Don't log private authentication messages!
*.info;mail.none;...
Linux日志管理Rsyslog入门 - C/C++ - 清泛网 - 专注IT技能提升
...g，其配置大致如下所示：
shell> cat /etc/syslog.conf
# Log all kernel messages to the console.
# Logging much else clutters up the screen.
# kern.* /dev/console
# Log anything (except mail) of level info or higher.
# Don't log private authentication messages!
*.info;mail.none;...
Linux日志管理Rsyslog入门 - C/C++ - 清泛网 - 专注IT技能提升
...g，其配置大致如下所示：
shell> cat /etc/syslog.conf
# Log all kernel messages to the console.
# Logging much else clutters up the screen.
# kern.* /dev/console
# Log anything (except mail) of level info or higher.
# Don't log private authentication messages!
*.info;mail.none;...