我们提供了大量的内置函数供用户使用。下面是一个内置函数的列表。只要在脚本开头写上 import greptime
或 from greptime import *
就可以调用它们。
Function |
Description |
pow(v0, v1) |
Raise a number v0 to a power of v1 . |
clip(v0, v1, v2) |
Clip all elements in a vector v0 to a range between vectors v1 and v2 . |
diff(v0) |
Calculate the difference between adjacent elements in a vector v0 . |
mean(v0) |
Calculate the mean of a vector v0 . |
polyval(v0, v1) |
Evaluate a polynomial v0 at points v1 . similar to numpy.polyval . |
argmax(v0) |
Return the index of the maximum value in a vector v0 . similar to numpy.argmax . |
argmin(v0) |
Return the index of the minimum value in a vector v0 . similar to numpy.argmin . |
percentile |
Calculate the q -th percentile of a vector v0 . similar to numpy.percentile . |
scipy_stats_norm_cdf |
Calculate the cumulative distribution function for the normal distribution. similar to scipy.stats.norm.cdf . |
scipy_stats_norm_pdf |
Calculate the probability density function for the normal distribution. similar to scipy.stats.norm.pdf . |
Function |
Description |
sqrt(v) |
Calculate the square root of a number v . |
sin(v) |
Calculate the sine of a number v . |
cos(v) |
Calculate the cosine of a number v . |
tan(v) |
Calculate the tangent of a number v . |
asin(v) |
Calculate the arcsine of a number v . |
acos(v) |
Calculate the arccosine of a number v . |
atan(v) |
Calculate the arctangent of a number v . |
floor(v) |
Calculate the floor of a number v . |
ceil(v) |
Calculate the ceiling of a number v . |
round(v) |
Calculate the nearest integer of a number v . |
trunc(v) |
Calculate the truncated integer of a number v . |
abs(v) |
Calculate the absolute value of a number v . |
signum(v) |
Calculate the sign(gives 1.0/-1.0) of a number v . |
exp(v) |
Calculate the exponential of a number v . |
ln(v) |
Calculate the natural logarithm of a number v . |
log2(v) |
Calculate the base-2 logarithm of a number v . |
log10(v) |
Calculate the base-10 logarithm of a number v . |
这些函数是由 DataFusion
绑定的。
Function |
Description |
random(len) |
Generate a random vector with length len . |
approx_distinct(v0) |
Calculate the approximate number of distinct values in a vector v0 . |
median(v0) |
Calculate the median of a vector v0 . |
approx_percentile_cont(values, percent) |
Calculate the approximate percentile of a vector values at a given percentage percent . |
array_agg(v0) |
Aggregate values into an array. |
avg(v0) |
Calculate the average of a vector v0 . |
correlation(v0, v1) |
Calculate the Pearson correlation coefficient of a vector v0 and a vector v1 . |
count(v0) |
Calculate the count of a vector v0 . |
covariance(v0, v1) |
Calculate the covariance of a vector v0 and a vector v1 . |
covariance_pop(v0, v1) |
Calculate the population covariance of a vector v0 and a vector v1 . |
max(v0) |
Calculate the maximum of a vector v0 . |
min(v0) |
Calculate the minimum of a vector v0 . |
stddev(v0) |
Calculate the sample standard deviation of a vector v0 . |
stddev_pop(v0) |
Calculate the population standard deviation of a vector v0 . |
sum(v0) |
Calculate the sum of a vector v0 . |
variance(v0) |
Calculate the sample variance of a vector v0 . |
variance_pop(v0) |
Calculate the population variance of a vector v0 . |
Method |
Description |
select_columns(columns: List[str]) |
select columns from DataFrame |
select(columns: List[Expr]]) |
select columns from DataFrame using PyExpr |
filter(condition: Expr) |
filter DataFrame using PyExpr |
aggregate(group_expr: List[Expr], aggr_expr: List[Expr]) |
Perform an aggregate query with optional grouping expressions. |
limit(skip: int, fetch: Optional[int]) |
Limit the number of rows returned from this DataFrame. skip - Number of rows to skip before fetch any row; fetch - Maximum number of rows to fetch, after skipping skip rows. |
union(other: DataFrame) |
Union two DataFrame |
union_distinct(other: DataFrame) |
Union two DataFrame, but remove duplicate rows |
distinct() |
Remove duplicate rows |
sort(expr: List[Expr]) |
Sort DataFrame by PyExpr , Sort the DataFrame by the specified sorting expressions. Any expression can be turned into a sort expression by calling its sort method. |
join(right: DataFrame, left_cols: List[str], right_cols: List[str], filter: Optional[Expr]) |
Join two DataFrame using the specified columns as join keys. Eight Join Types are supported: inner , left , right , full , leftSemi , leftAnti , rightSemi , rightAnti . |
intersect(other: DataFrame) |
Intersect two DataFrame |
except(other: DataFrame) |
Except two DataFrame |
collect() |
Collect DataFrame to a list of PyVector |
Method |
Description |
col(name: str) |
Create a PyExpr that represents a column |
lit(value: Any) |
Create a PyExpr that represents a literal value |
sort(ascending: bool, null_first: bool) |
Create a PyExpr that represents a sort expression |
comparison operators: == , != , > , >= , < , <= |
Create PyExpr from compare two PyExpr |
logical operators: & , | , ~ |
Create PyExpr from logical operation between two PyExpr |