数据操控
方法 | 描述 | melt(frame[, id_vars, value_vars, var_name, …]) “Unpivots” a DataFrame from wide format to long format, optionally leaving pivot(index, columns, values) 创建透视表 pivot_table(data[, values, index, columns, …]) 创建透视表 crosstab(index, columns[, values, rownames, …]) Compute a simple cross-tabulation of two (or more) factors. cut(x, bins[, right, labels, retbins, …]) Return indices of half-open bins to which each value of x belongs. qcut(x, q[, labels, retbins, precision]) Quantile-based discretization function. merge(left, right[, how, on, left_on, …]) 融合表格，类似SQL的连表 merge_ordered(left, right[, on, left_on, …]) Perform merge with optional filling/interpolation designed for ordered data like time series data. merge_asof(left, right[, on, left_on, …]) Perform an asof merge. concat(objs[, axis, join, join_axes, …]) 连接两个表格 get_dummies(data[, prefix, prefix_sep, …]) Convert categorical variable into dummy/indicator variables factorize(values[, sort, order, …]) Encode input values as an enumerated type or categorical variable顶层缺失值方法
方法 | 描述 | isnull(obj) 检测丢失值 notnull(obj) Replacement for numpy.isfinite / -numpy.isnan which is suitable for use on object arrays.顶层类型转换方法
方法 | 描述 | to_numeric(arg[, errors, downcast]) 转换为数字格式顶层时间方法
方法 | 描述 | to_datetime(*args, **kwargs) 转换为datetime类型 to_timedelta(*args, **kwargs) 转换为datedelta类型 date_range([start, end, periods, freq, tz, …]) 生成时间序列 bdate_range([start, end, periods, freq, tz, …]) 生成工作时间序列 period_range([start, end, periods, freq, name]) 生成固定频率的时间索引 timedelta_range([start, end, periods, freq, …]) 生成固定频率的timedelta索引 infer_freq(index[, warn]) Infer the most likely frequency given the input index.顶层评估方法
方法 | 描述 | eval(expr[, parser, engine, truediv, …]) Evaluate a Python expression as a string using various backends. 0 0
